Leeds trolleybus (NGT - new generation transport)

[edwin_m]

I suggest it's difficult to justify a trolleybus because they fit into a relatively small transport niche between buses and trams.

A diesel or hybrid bus can be the same size as a trolleybus so with equivalent segregated infrastructure can provide the same passenger capacity and almost the same journey times as a trolleybus. However it can also run on unmodified roads, though either type of bus is then affected (again equally) by traffic congestion. State-of-the-art self-powered buses minimise local noise and pollution and because they can capitalise on innovations aimed at the huge road vehicle market, they are likely to keep getting better as time goes on. For similar reasons buses are always likely to be a lot cheaper than a trolleybus.

The tram comes into its own on the busiest routes. Trams can be larger than trolleybuses and steel wheel uses a lot less energy than rubber tyres, so a well-filled tram has lower running costs per passenger. Capital cost will be somewhat greater due to the rails and more expensive vehicles, but for high capacity a transit route of any type needs a high degree of segregation. This implies diversion of utilities (to avoid disruption from future maintenance) and probably also a concrete slab road surface (to avoid rutting on asphalt services used intensively by heavy buses). Potentially this is not much cheaper than a street tramway, and may even be more expensive in areas where the tramway alternative could use ballasted track.

In general the self-powered bus will offer the most cost-effective solution when passenger flows are relatively low and segregated infrastructure is needed only on short sections of route, as with the guided buses in Leeds. The tram will be most cost-effective at high passenger flows and where nearly all the route needs to be segregated. The question is whether there are any in-between routes where the trolleybus is the best answer. It does also remain an option for cities with special problems such as steep hills and particularly bad local pollution issues.

 

[JohnB57]

The Spen Valley Line would be a good candidate for re-opening, the track bed is practically intact aside from redevelopment around the Low Moor area and a small intrusion at Cleckheaton, still no re-opening campaign. Still no station at Elland, despite the line through the town being open well over 10 years. I could go on.

The Spen line could only realistically be reconnected with the Healey Mills/Calder Valley line in the Wakefield direction which would offer additional services far too limited to be viable.

The thing is, in between Marsden and Ravensthorpe extra tracks could be accommodated to increase capacity.

The scope for this is quite limited. Up the Colne Valley, the line was slewed in 1979 to allow higher line speeds and this now takes up most of the trackbed on the bends. Reversing this would reduce line speed. To the east of Huddersfield, the trackbed is not uniformly wide enough to re-quadruple so the benefits would again be marginal.

"Wireless trolleybuses" require ridiculous amounts of roadwork, if you are referring to the systems that use conductors embedded in the road surface.
They are also rather troublesome with all the high power RF generators you need.

And I would question the idea that modern trolleybus wire installations cause significant loss of "visual amenity", infact housing and commercial properties near trolleybus routes on the continent tend to have higher values because it is a visual indication of the high quality of public transport the area recieves.

"Wireless" in this context doesn't mean RF. It means "without wires". Of course, your tongue could be firmly in your cheek...

Trolleybus cabling involves two conductor wires so it is a little more intrusive than that for trams. For the same reason, on junctions cabling is quite complex and would require additional switching equipment activated from the cab. No reason to reject trolleybuses but something to consider.

 

[HSTEd]

I suggest it's difficult to justify a trolleybus because they fit into a relatively small transport niche between buses and trams.

A diesel or hybrid bus can be the same size as a trolleybus so with equivalent segregated infrastructure can provide the same passenger capacity and almost the same journey times as a trolleybus.

But trolleybuses are significantly more rapidly accelerating than even hybrid buses, since a) they have far more power available and b) they are able to be less 'frugal' because in a hybrid bus all your energy is derived from diesel and is thus rather expensive, I come out at a price of nearly 30p/kWh at current buss-diesel prices.

However it can also run on unmodified roads, though either type of bus is then affected (again equally) by traffic congestion. State-of-the-art self-powered buses minimise local noise and pollution and because they can capitalise on innovations aimed at the huge road vehicle market, they are likely to keep getting better as time goes on. For similar reasons buses are always likely to be a lot cheaper than a trolleybus.

The primary reason for the "increased capital cost" of trolleybuses is that they are currently a bespoke market in western europe, in eastern europe they cost a similar amount to comparabe diesel buses and there is every reason to expect that this would occur in the west if significant numbers of vehicles were ordered.
Remember that these buses, if using a battery off-wire supply, can have pretty much no moving parts these days thanks to innovations in wheel-hub motor assemblies.
The slashed maintenance costs have to count for something.

The tram comes into its own on the busiest routes.

If and only if a practical segregated right of way exists which can be exploited, this is not the case in many cases (such as the Oxford Road Corridor in Manchester).

Trams can be larger than trolleybuses and steel wheel uses a lot less energy than rubber tyres, so a well-filled tram has lower running costs per passenger. Capital cost will be somewhat greater due to the rails and more expensive vehicles, but for high capacity a transit route of any type needs a high degree of segregation.

No it doesn't, again see the Oxford Road Corridor in Manchester, my experiene of numerous streets in London and various other places.
I believe in rush hour the capacity on Oxford road approaches fifty buses per hour per direction if not more.

This implies diversion of utilities (to avoid disruption from future maintenance) and probably also a concrete slab road surface (to avoid rutting on asphalt services used intensively by heavy buses).

Neither of these things has been undertaken in Manchester, and rutting of an asphalt surface would require that the trolleybuses run over the exact same portion fo the road surface over and over, which would not normally happen because a trolleybus has a couple of feet of leeway in both directions.
--- old post above --- --- new post below ---

"Wireless" in this context doesn't mean RF. It means "without wires". Of course, your tongue could be firmly in your cheek...

Most of the systems for wirelessly transmitting power to a vehicle continuously during operation involve an inductive coil system in the road surface which operates in the kHz range to induce currents in a coil slung under the vehicle.

The signal generators required to produce such a power supply frequency are not 100% reliable and maintenance-free.
It also means that if it malfunctions you have to dig up the road to get to it.

Intermittant charging at stops is also problematic unless you have a fully segregated route as a traffic jam can easily trap a bus for sufficient amount of time to run down its battery on its auxiliaries, especially if they are the auxiliaries one would fit to a conventional trolleybus.
The need to ensure that you have sufficient power to make the next charging point means that all buses would have to stop at all stops even if they are full and unable to take on additional passengers, causing serious operational problems the bus operators/dispatchers and confusion for passengers.

Trolleybus cabling involves two conductor wires so it is a little more intrusive than that for trams. For the same reason, on junctions cabling is quite complex and would require additional switching equipment activated from the cab. No reason to reject trolleybuses but something to consider.

From my experience of walking around under trolleybus systems on the continent they appear to be little more intrusive than the mass of span wires and cantilevers strung over the road between the Arndale and Piccadilly Gardens to support Metrolink.

It appears they just fade into the background and most people do not notice them, but they will notice the fact that the air seems significantly fresher when a significant quantity of diesel engines are removed from the vicinity.
(Conventional trolleybus systems can also share ~750V power supplies with nearby light rail routes, essentially creating an ad-hoc 750VDC 'grid' in city centres and along transport corridors that will allow new lines in both systems to be more cheaply and easily provided)

 

[edwin_m]

But trolleybuses are significantly more rapidly accelerating than even hybrid buses, since a) they have far more power available and b) they are able to be less 'frugal' because in a hybrid bus all your energy is derived from diesel and is thus rather expensive, I come out at a price of nearly 30p/kWh at current buss-diesel prices.

That's why I said a diesel bus would have slightly longer journey times. Hybrid buses can overcome this to some extent by using stored energy to boost acceleration rates.

The primary reason for the "increased capital cost" of trolleybuses is that they are currently a bespoke market in western europe, in eastern europe they cost a similar amount to comparabe diesel buses and there is every reason to expect that this would occur in the west if significant numbers of vehicles were ordered.

Interested to see some evidence of this. If there is already sizeable production of vehicles of suitable standard to an off-the-shelf design then someone in the West could just order some.

Remember that these buses, if using a battery off-wire supply, can have pretty much no moving parts these days thanks to innovations in wheel-hub motor assemblies.
The slashed maintenance costs have to count for something.

Some, but I grant you not all, of this will also apply to diesel/hybrid buses which are also likely to move to similar drive technology.

If and only if a practical segregated right of way exists which can be exploited, this is not the case in many cases (such as the Oxford Road Corridor in Manchester).

No it doesn't, again see the Oxford Road Corridor in Manchester, my experiene of numerous streets in London and various other places.
I believe in rush hour the capacity on Oxford road approaches fifty buses per hour per direction if not more.

I agree Oxford Road wouldn't be a suitable alignment for Metrolink but I can't see trolleybuses working there either. Replacing all the diesel buses by trolleybuses of similar size might improve the environment (as would replacing all the ancient ones by more modern ones) but would do nothing for the capacity, and would in fact make it worse unless there was a reliable method for them to overtake each other (leading to bunching etc).

Replacing diesel buses by the largest feasible design of articulated trolleybus would improve the capacity or reduce the number of vehicles, but so would replacing by articulated diesel buses of the same size. If there was no overtaking the trolleybuses would always be lower capacity than an equivalent tram, because the spacing between vehicles would be the same (dictated by stop dwell times) but the trolleybuses would be smaller than the trams. The benefit of overtaking reduces as the vehicles get bigger, as it becomes less and less likely that one can run past a particular stop.

Metrolink on Mosley Street will run around 40 services per hour on completion of Phase 3, some of which will be coupled pairs. In terms of passengers this is more capacity than 50 buses.

There would also need to be a way of persuading multiple operators to co-operate on a single route.

Neither of these things has been undertaken in Manchester, and rutting of an asphalt surface would require that the trolleybuses run over the exact same portion fo the road surface over and over, which would not normally happen because a trolleybus has a couple of feet of leeway in both directions.

Where in Manchester are you referring to? There was certainly rutting at Piccadilly Gardens prior to the resurfacing a couple of months back. For level boarding the trolleybuses would have to follow exactly the same path at stops, probably with some form of guidance, and the same might well apply if there was a need to minimise land take elsewhere, for example to take up the same amount of space as a tramway.

From my experience of walking around under trolleybus systems on the continent they appear to be little more intrusive than the mass of span wires and cantilevers strung over the road between the Arndale and Piccadilly Gardens to support Metrolink.

That's a bad example. The builders in 1992 decided, for reasons best known to themselves, to provide a special typhoon-proof overhead developed for Hong Kong, which not surprisingly is a lot heavier than it needs to be. See Sheffield, Nottingham and numerous Continental cities for better examples of tramway overhead in city centres. By its very nature a trolleybus overhead will have twice as many contact wires so if tram overhead is seen as a problem then trolleybus overhead will be seen as twice as bad.

(Conventional trolleybus systems can also share ~750V power supplies with nearby light rail routes, essentially creating an ad-hoc 750VDC 'grid' in city centres and along transport corridors that will allow new lines in both systems to be more cheaply and easily provided)

You wouldn't distribute traction power at 750V over any distance as the power losses would be too great - that's why tramways and trolleybuses need substations every 1-2km. In urban areas there are generally plenty of higher-voltage lines around to feed them from. There might be marginal savings from combining a tram and trolleybus substation.

 

[JohnB57]

Most of the systems for wirelessly transmitting power to a vehicle continuously during operation involve an inductive coil system in the road surface which operates in the kHz range to induce currents in a coil slung under the vehicle.

From my experience of walking around under trolleybus systems on the continent they appear to be little more intrusive than the mass of span wires and cantilevers strung over the road between the Arndale and Piccadilly Gardens to support Metrolink.

kHz doesn't necessarily equate to RF - conventionally, radio frequency starts at 300kHz - but I'd be fascinated to read any links you have for this as most inductive power transfer applications are high frequency in AC terms, but well below that and the interference implications are unthinkable and probably unlicenceable.

Don't think for a minute that I'm anti trolleybus by the way - quite the opposite. I'm enough of an anorak to spend hours studying old pictures of complex junction wiring and frog systems and I'm emphatically in favour.

73 de G0SJB

 

[DW54]

"Wireless trolleybuses" require ridiculous amounts of roadwork, if you are referring to the systems that use conductors embedded in the road surface.
They are also rather troublesome with all the high power RF generators you need.

Conventional trolleybuses are cheaper, require far fewer hugely disruptive road closures to be routed over roads and thus can be expanded far more easily and cheaply.

And I would question the idea that modern trolleybus wire installations cause significant loss of "visual amenity", infact housing and commercial properties near trolleybus routes on the continent tend to have higher values because it is a visual indication of the high quality of public transport the area recieves.

No way, José. I'm talking about electric buses that get their power via any of a number of methods, but in this particular case - to support the legal lunacy - I'm suggesting stringing wires in non-sensitive straight-ish line sections, and letting a combination of batteries, KERS and supercaps provide the power in the gaps. Of course, auto-rewiring is part of the plan.

That way, it's really a trolleybus system (legally) but without the negatives of:
a) high cost of comprehensive overhead, wired junctions and tight curves and depots; plus
b) loss of visual amenity,
c) operational inflexibility and
d) supply-fault intolerance.

The last thing you want with a fully-wired system is loss of power, and a small system is unlikely to be able to draw from multiple discrete points in the national grid.

Now, looking at the issue of inductive power supply, I see these as being restricted to specific locations if they're used at all. Otherwise, a "wireless" trolley sysyem could be charged from short sections of wiring. Where all of these are on guideway, a single-wire AC supply could be possible (but AFAIK untried) - otherwise conventional DC two-wire.

And please come back to my suggested strategy of building up the road infrastructure side, and as each part is completed - serve it with diesel or hybrid vehicles out of the existing fleets (under contract?). Only once the travel time benefits are proven, AND the Council has failed to get the planning and operational co-ordination arrangements it seeks - THEN put up enough wires and acquire enough suitable "flexi-trolleybuses" to activate the legal distinction.

If Council HAS got the co-ordination controls it seeks, then all forms of electric bus could then be assessed to contribute to a progressive and "clean" fleet replacement strategy, benefitting all of Leeds, not just a few key routes.

 

[HSTEd]

Interested to see some evidence of this. If there is already sizeable production of vehicles of suitable standard to an off-the-shelf design then someone in the West could just order some.

Look to trolleybuses in China which tend towards comparable purchase costs to conventional buses, especially hybrid ones.
An off the shelf design suitable for use in China is not really going to be useful here for a variety of obvious reasons, especially that they are single deck short vehicles since they don't have anything like the intensity of service we have here.

Some, but I grant you not all, of this will also apply to diesel/hybrid buses which are also likely to move to similar drive technology.

Diesel/hybrid buses will always be higher maintenance because the intensive use you require from the diesel enigne will mean it will always require substantial amounts of maintenance itself.

I agree Oxford Road wouldn't be a suitable alignment for Metrolink but I can't see trolleybuses working there either. Replacing all the diesel buses by trolleybuses of similar size might improve the environment (as would replacing all the ancient ones by more modern ones) but would do nothing for the capacity, and would in fact make it worse unless there was a reliable method for them to overtake each other (leading to bunching etc).

Bunching on Oxford Road tends to be a problem anyway, but regardless the number of stops where it is a significant issue is relatively small so it would be relatively simple to simply put in wire switches to put the stop's wiring on a parallel line to the non stop wire.

The route is so intensive that you could potentially make a case for quad-lining the section between the RNCM and Oxford Road railway station, assuming you convert the 85/86 sub-corridor as well as the x4x routes.

Replacing diesel buses by the largest feasible design of articulated trolleybus would improve the capacity or reduce the number of vehicles, but so would replacing by articulated diesel buses of the same size.

Articulated buses are an absolute no-no.
Look at the political outcry they caused in London when used on intensive routes. It has to be double deckers which unfortunately means some sort of bespoke double decker trolley design, but considering the size of the order to reequip the Oxford Road corridor and its attached routes this should not be a problem.

If there was no overtaking the trolleybuses would always be lower capacity than an equivalent tram, because the spacing between vehicles would be the same (dictated by stop dwell times) but the trolleybuses would be smaller than the trams. The benefit of overtaking reduces as the vehicles get bigger, as it becomes less and less likely that one can run past a particular stop.

But a tram route is not practical on most routes, nevermind how absurdly expensive light rail is these days. The amount of demolition required for dedicated right of way transport simply makes large scale deployment in a crowded urban environment near impossible.

Note how Metrolink relies on converting heavy rail lines or reopening old lines most of the time.

Metrolink on Mosley Street will run around 40 services per hour on completion of Phase 3, some of which will be coupled pairs. In terms of passengers this is more capacity than 50 buses.

Yes, but I have spent considerable amounts of thinking time since September 2008 (when I arrived in South Manchester) trying to thread a useful tram route through the Oxford Road corridor and failed every time, you simply need too many demolitions which simply cost far too much.
If we are going to have improvements it has to use the existing road alignment.
The same is true in numerous cases across the country.

There would also need to be a way of persuading multiple operators to co-operate on a single route.

Simple, the council decommision the bus lanes and ban all non-electric vehicles from them during the hours that they are currently public transport-only.
They either use trolleybuses or they don't run at all.

Where in Manchester are you referring to? There was certainly rutting at Piccadilly Gardens prior to the resurfacing a couple of months back. For level boarding the trolleybuses would have to follow exactly the same path at stops, probably with some form of guidance, and the same might well apply if there was a need to minimise land take elsewhere, for example to take up the same amount of space as a tramway.

Rutting at stops is not really a major issue since the majority of stops along the route are set back from the road, and as such vehicles do not run over them at high speed.
There would be no more rutting on the road itself than conventional buses.
And why would there be some form of guidance at the stops since there is no guidance now?

That's a bad example. The builders in 1992 decided, for reasons best known to themselves, to provide a special typhoon-proof overhead developed for Hong Kong, which not surprisingly is a lot heavier than it needs to be. See Sheffield, Nottingham and numerous Continental cities for better examples of tramway overhead in city centres. By its very nature a trolleybus overhead will have twice as many contact wires so if tram overhead is seen as a problem then trolleybus overhead will be seen as twice as bad.

The majority of the lines in the overhead rigging are nothing to do with the contact wires, they are to do with supporting the entire system.
At worst the doubling of the number of contact wires will require the cross sectional area of the supporting wire to double, which means that its optical diameter will increase by a factor of root-2.... not 2.
So it will be nowhere near twice as bad, and in reality most of the wires will not need to increase significantly in size due to them being ludicrously overspecced as the structural loading on the installation is not the primary driver for chosing wire diameters. (Various wire sizes are more easily available and are thus cheaper and thus are chosen even if they are insanely overspecified for the task required).

You wouldn't distribute traction power at 750V over any distance as the power losses would be too great - that's why tramways and trolleybuses need substations every 1-2km. In urban areas there are generally plenty of higher-voltage lines around to feed them from. There might be marginal savings from combining a tram and trolleybus substation.

You forget how far 2km will get you in a city centre.
For instance a single substation in Picadilly gardens could support 6km of tram line and 2km of trolleybus route (which gets you as far as the UMSU building adjacent to the Manchester museum).

The marginal savings would allow you to more cheaply deploy new wire routes for both tramway and trolleybus as required by operational extingencies.
--- old post above --- --- new post below ---

No way, José. I'm talking about electric buses that get their power via any of a number of methods, but in this particular case - to support the legal lunacy - I'm suggesting stringing wires in non-sensitive straight-ish line sections, and letting a combination of batteries, KERS and supercaps provide the power in the gaps. Of course, auto-rewiring is part of the plan.

That way, it's really a trolleybus system (legally) but without the negatives of:
a) high cost of comprehensive overhead, wired junctions and tight curves and depots; plus

You baulk at the high cost of overhead and then decide to embrace expensive technologies like batteries, supercaps and KERS?
KERS has potential safety issues that require enormously heavy armouring for the rotor assembly to prevent it spontaneously dissasembling in an accident, batteries require replacing every few years if used heavily and supercapacitors provide so little power that a single traffic jam could easily leave a vehicle stranded.

Overhead wire switches cost ~£10,000 each according to research I managed to dig up, slightly more if they are designed for higher speeds, which most complex junctions will emphatically not be.

b) loss of visual amenity,

Loss of visual amenity is one of those things that everyone complains about but then after a few years of the wires being in place, noone cares about any more.
And frankly most inner city routes have few buildings of architectural significance that will be seriously affected.

c) operational inflexibility and

You don't have much flexibility if you require battery jumps since you will be range limited to a degree that after you consider the distance between the electrified sections you will have little left to divert around obstructions.
With a fully wired system what battery or generic APU capacity you have can be used purely to divert around the obstacle.

d) supply-fault intolerance.

The last thing you want with a fully-wired system is loss of power, and a small system is unlikely to be able to draw from multiple discrete points in the national grid.

How long do you think KERS/Supercap/Battery buses will last with a systemwide loss of power? (Since a small system would also be unable to connect its charging stations to multiple discrete points on the national grid).
You end up with the same result, just delayed by a handful of minutes.

Now, looking at the issue of inductive power supply, I see these as being restricted to specific locations if they're used at all. Otherwise, a "wireless" trolley sysyem could be charged from short sections of wiring. Where all of these are on guideway, a single-wire AC supply could be possible (but AFAIK untried) - otherwise conventional DC two-wire.

The short sections of wiring approach was attempted in Shanghai.... you had to have all the big support masts/cables that are required for trolleybuses and all you saved were the contact wires themselves.
Pulsing the supply like that also tends to increase your peak power demand on the system (since you are drawing the same amount of energy in half or less of the time) which means you need bigger substations, bigger supply cables and half a dozen other things.

And please come back to my suggested strategy of building up the road infrastructure side, and as each part is completed - serve it with diesel or hybrid vehicles out of the existing fleets (under contract?).

Road infrastructure improvements of the kind that would make any difference are simply impractical on most routes, the roads simply aren't wide enough and widening them to allow bus only lanes to be added over entire routes would be simply impractical. I estimate less than 30% of the Oxford Road corridor in Manchester, (the route grouping I have studied in most detail) can be placed in bus exclusive lanes, the rest must share the road space otherwise available (in South Manchester including the worst bottleneck of all - the curry mile)

Only once the travel time benefits are proven, AND the Council has failed to get the planning and operational co-ordination arrangements it seeks - THEN put up enough wires and acquire enough suitable "flexi-trolleybuses" to activate the legal distinction.

But this isn't primarily about travel times, this is about improving air quality in currently choked transport corridors and improving ridership through improved ride quality due to reduced vibrations and the ability to include value added extras at far reduced operating cost (chiefly air conditioning).

If Council HAS got the co-ordination controls it seeks, then all forms of electric bus could then be assessed to contribute to a progressive and "clean" fleet replacement strategy, benefitting all of Leeds, not just a few key routes.

I wasn't really talking about Leeds, I am talking generally and using S. Manchester as an example, and frankly Trolleybuses are the only kind of electric bus that is every going to be practical on a large scale, current battery technology is not advanced enough and the more rapid charging required to make it practical will likely collapse the grid if used on a large scale.

It is the fundamental problem with battery electric vehicles.

 

[61653 HTAFC]

There must also be places on the routes for which visual amenity is a valued local asset...

I can only assume you've not been to Leeds much, then!

Seriously though, I'm in favour of anything that will increse modal-shift: something that the ftr spectacularly failed to do on the route 4 in both Leeds and York (now they've been deployed on the Leeds-Bradford 72 I have a feeling most of the increased patronage has come from people fed up of squeezing onto 2-car DMUs at Bradford Interchange rather than giving up their cars!) and something that trams would be better at than the trolleybuses- but the trolleybuses will at least have a fighting chance. So basically, I'm pro-trolleybuses but with the slight caveat that the original shelved tram project would've been better.

I also wish WYPTE would get over their fixation with tram-trains, given that they don't even have a regular tramway to run it onto. Also, Sheffield would be a better example to follow than Manchester when it comes to trams, simply because nowhere in South Yorkshire has lost it's heavy-rail links in favour of trams- and there's no routes in West Yorkshire that would be appropriate for conversion- least of all Harrogate/Knaresborough!

 

[DW54]

" Bunching on Oxford Road tends to be a problem anyway,

" Articulated buses are an absolute no-no.

" Look at the political outcry they caused in London when used on intensive routes

" ... reequip the Oxford Road corridor and its attached routes this should not be a problem.


" Note how Metrolink relies on converting heavy rail lines or reopening old lines most of the time.

"... useful tram route through the Oxford Road corridor and failed every time,

" The majority of the lines in the overhead rigging are nothing to do with the contact wires, they are to do with supporting the entire system.
At worst the doubling of the number of contact wires will require the cross sectional area of the supporting wire to double, which means that its optical diameter will increase by a factor of root-2.... not 2.
" So it will be nowhere near twice as bad,

" You forget how far 2km will get you in a city centre.
For instance a single substation in Picadilly gardens could support 6km of tram line and 2km of trolleybus route (which gets you as far as the UMSU building adjacent to the Manchester museum).

--- old post above --- --- new post below ---


You baulk at the high cost of overhead and then decide to embrace expensive technologies like batteries, supercaps and KERS?
KERS has potential safety issues that require enormously heavy armouring for the rotor assembly {snip} batteries require replacing every few years if used heavily and supercapacitors provide so little power that a single traffic jam could easily leave a vehicle stranded.

Overhead wire switches cost ~£10,000 each according to research I managed to dig up, slightly more if they are designed for higher speeds, which most complex junctions will emphatically not be.

"Loss of visual amenity is one of those things that everyone complains about but then after a few years of the wires being in place, noone cares about any more.
"And frankly most inner city routes have few buildings of architectural significance that will be seriously affected.

" You don't have much flexibility if you require battery jumps since you will be range limited to a degree that after you consider the distance between the electrified sections you will have little left to divert around obstructions.
With a fully wired system what battery or generic APU capacity you have can be used purely to divert around the obstacle.

" How long do you think KERS/Supercap/Battery buses will last with a systemwide loss of power? (Since a small system would also be unable to connect its charging stations to multiple discrete points on the national grid).
You end up with the same result, just delayed by a handful of minutes.

" The short sections of wiring approach was attempted in Shanghai.... you had to have all the big support masts/cables that are required for trolleybuses and all you saved were the contact wires themselves.
Pulsing the supply like that also tends to increase your peak power demand on the system (since you are drawing the same amount of energy in half or less of the time) which means you need bigger substations, bigger supply cables and half a dozen other things.

" Road infrastructure improvements of the kind that would make any difference are simply impractical on most routes, the roads simply aren't wide enough and widening them to allow bus only lanes to be added over entire routes would be simply impractical. I estimate less than 30% of the Oxford Road corridor in Manchester, (the route grouping I have studied in most detail) can be placed in bus exclusive lanes, the rest must share the road space otherwise available (in South Manchester including the worst bottleneck of all - the curry mile)

"But this isn't primarily about travel times, this is about improving air quality in currently choked transport corridors and improving ridership through improved ride quality due to reduced vibrations and the ability to include value added extras at far reduced operating cost (chiefly air conditioning).

I wasn't really talking about Leeds, I am talking generally and using S. Manchester as an example, and frankly Trolleybuses are the only kind of electric bus that is every going to be practical on a large scale, current battery technology is not advanced enough and the more rapid charging required to make it practical will likely collapse the grid if used on a large scale.

It is the fundamental problem with battery electric vehicles.

Crikey HSTed, you seem to be building a Manchester system when the subject was a Leeds system which primarily offered travellers reduced travel time.

Seeing as that was the FIRST objective of NGT, I'm suggesting it's the first outcome they want to achieve. The second and third objectives are clean air and minimised long-term life-cost, in whichever order.

So for Leeds specifically, I've suggested prove out the travel time savings with non-bespoke technologies; then assess the maturity and life-cost of appropriate technologies at the time - taking into account the legal situation.

To suggest people get used to visual intrusion and therefore visual amenity can be discounted is the "frog in a pot of water argument". HSTed, you do spout a load of cobblers at times.

The NGT for Leeds is predicated entirely on a legal nonsense, and what I'm putting on the table is a strategy to minimise financial commitment while all angles to work around the DafT legal situation are refined - and to buy time while emergent technologies mature.

You rubbish storage systems such as battery, supercap and KERS. Taken alone, each one has deficiencies. I'm suggesting using them in a complementary way. The Supercap is a short-term storage system. It stores the peak pulse of energy recovered during regenerative braking, and either releases it slowly to the batteries or releases it quickly during acceleration. KERS can hold more energy than supercap, so is more useful when handling downhill-uphill, and the batteries basically pick up the primary charge from external sources and maintain auxilliaries and the traction load averaged along the line of route by the supercaps and KERS.

Taken together, the loads on the overhead where it is installed would be no more than the "pulsing" peaks of acceleration and regenerative braking that occur on a fully wired system with only emergency batteries.

I have already said that a 40km or 1 hour range would be the target for fail-graceful. You might have missed that. In fact, to be a tad more scientific: I would suggest that a statistical analysis of the duration of outages of industrial power supply in the region be undertaken, and the range be set at about the 95%ile of that distribution.

With regenerative braking, the fact that the storage technologies are heavy is of less importance economically - but non-zero for sure. There is ongoing research and development in each of these areas, so it would be wise to defer actual purchase as long as possible, so that the most mature and proven of the emergent systems can be compared to a traditional all-wired system on life cost and community amenity (using the Leeds community's interpretation, not yours). I'm expecting that the liaison between the racing industry and the traction industry on KERS will lead to light, reliable KERS packages. With electric drive, an inductive flywheel can be used for the KERS, reducing the number of wearing parts and maintenance workload.

I had posted about NaHx batteries - but I was guilty of faulty memory - these are high-temperature, fixed installation batteries. GE have launched their Durathon, with some explanation here: http://www.getransportation.com/ene...ights-durathon-battery-and-ge-innovation.html

"Mar / 17

CNN Spotlights Durathon Battery and GE Innovation

A recent CNN Money report highlights GE’s culture of innovation, including GE Transportation’s new Durathon battery. The Durathon battery is the product of GE’s $150 million investment in next-generation batteries, and is scheduled for production later this year in Schenectady, New York.

Durathon is a sodium-metal halide battery for the telecommunications industry, uninterruptable power supply (UPS), and utilities markets. The Durathon battery acts as a backup power supply for industries that would suffer significantly from an interruption in power.

Durathon differentiates itself by storing vast amounts of energy in a very small space – it is 50% the footprint and less than 25% the weight of traditional lead acid batteries. In addition, Durathon batteries can last up to 20 years, operate effectively in extreme temperatures, are recyclable, and require no cooling and only minimal maintenance. More information on Durathon can be found here: http://www.geenergystorage.com/telecom.html

If you follow through the links, you will find that GE are combining the NaMh battery with a Lithium battery to obtain an optimum mix of characteristics. The Li battery could also be complemented/replaced in these configurations by Supercaps and KERS.

 

[edwin_m]

Look to trolleybuses in China which tend towards comparable purchase costs to conventional buses, especially hybrid ones.
An off the shelf design suitable for use in China is not really going to be useful here for a variety of obvious reasons, especially that they are single deck short vehicles since they don't have anything like the intensity of service we have here

...

Articulated buses are an absolute no-no.
Look at the political outcry they caused in London when used on intensive routes. It has to be double deckers which unfortunately means some sort of bespoke double decker trolley design, but considering the size of the order to reequip the Oxford Road corridor and its attached routes this should not be a problem.

So you're saying that prices will be low if we get an off-the-shelf design, but no suitable off-the-shelf design is available so we will have to have a bespoke one, which to me says it will still be expensive.

Nowhere else would want double deckers so you'd have to persuade several UK authorities to make simultaneous purchases of double-deck trolleybuses, where there's no sign of any of them wanting any at the moment. Also if several projects shared an order then any one of them failing to go ahead (not exactly rare in the UK) probably also brings down all the others.

Double deckers also drastically increase stop dwell time, especially if they are larger and still have the multiplicity of operators and fares rather than a simple flat fare, smart-card of pre-purchase system.

Diesel/hybrid buses will always be higher maintenance because the intensive use you require from the diesel enigne will mean it will always require substantial amounts of maintenance itself.

I agree, but like all the other advantages the trolleybus has over the diesel/hybrid, the gap will reduce as technology advances.

Bunching on Oxford Road tends to be a problem anyway, but regardless the number of stops where it is a significant issue is relatively small so it would be relatively simple to simply put in wire switches to put the stop's wiring on a parallel line to the non stop wire.

You'd need to do this at every stop, in fact arguably it is more needed at the minor stops than the major ones because the occasional trolleybus stopping there will cause several others to queue up behind. Especially so with the dwell time implications of double deckers.

But a tram route is not practical on most routes, nevermind how absurdly expensive light rail is these days. The amount of demolition required for dedicated right of way transport simply makes large scale deployment in a crowded urban environment near impossible.

Note how Metrolink relies on converting heavy rail lines or reopening old lines most of the time.

Yes, but I have spent considerable amounts of thinking time since September 2008 (when I arrived in South Manchester) trying to thread a useful tram route through the Oxford Road corridor and failed every time, you simply need too many demolitions which simply cost far too much.
If we are going to have improvements it has to use the existing road alignment.
The same is true in numerous cases across the country.

As I said previously I agree Oxford Road is not a sensible corridor for trams, though routes such as the Didsbury Metrolink might take some of the longer-distance passengers off Oxford Road.

The point at issue is whether trolleybuses would be an improvement. Since in the form you propose they would simply substitute electric traction for diesel hybrid while keeping the same number and size of vehicle, then I suggest the benefit is limited to a small saving in journey time and operating cost, and the reduction of local noise and emissions.

Rutting at stops is not really a major issue since the majority of stops along the route are set back from the road, and as such vehicles do not run over them at high speed.
There would be no more rutting on the road itself than conventional buses.
And why would there be some form of guidance at the stops since there is no guidance now?

There was still rutting at Piccadilly Gardens as I mentioned, where speeds are very low. The issue is more the pressure exerted by the tyres rather than the effects of vehicle speed.

A modern transit system would expect to have reliable level boarding for wheelchairs etc, and the dwell time consequences of deploying a ramp would be unacceptable if you are trying to reduce journey times and increase capacity. So the vehicles will have to stop reliably within a lateral tolerance of an inch or two, with or without guidance, and this is the issue that leads to rutting.

You forget how far 2km will get you in a city centre.
For instance a single substation in Picadilly gardens could support 6km of tram line and 2km of trolleybus route (which gets you as far as the UMSU building adjacent to the Manchester museum).

It is typically 1km in a city centre because the route is busier. Trolleybuses carrying the same total number of passengers are likely to need closer-spaced substations because of their increased energy consumption. There is also a tradeoff beween overhead line cross section and substation spacing.

reduced vibrations

A lot of the discomfort on a bus arises from the reaction of the suspension to an imperfect road surface, or the lateral accelerations from imperfect cornering. These would be the same with a trolleybus unless it was also provided with a solid concrete slab and with guidance respectively

I note that some of the quotes in HSTEd's previous post were attributed to me but actually came from someone else.

 

[DW54]

I can only assume you've not been to Leeds much, then!

Seriously though, I'm in favour of anything that will increse modal-shift: something that the ftr spectacularly failed to do on the route 4 in both Leeds and York (now they've been deployed on the Leeds-Bradford 72 I have a feeling most of the increased patronage has come from people fed up of squeezing onto 2-car DMUs at Bradford Interchange rather than giving up their cars!) and something that trams would be better at than the trolleybuses- but the trolleybuses will at least have a fighting chance. So basically, I'm pro-trolleybuses but with the slight caveat that the original shelved tram project would've been better.

Good gracious, the "ftr" is retro if I ever saw "retro". Think 1930s streamlining gone berserk. Useless design unless you're providing a free shuttle. Certainly no route bus. At some point, driver interaction is needed - to assist the unfamiliar, the disabled, etc. Bad to design it out. Makes any form of DOO very hard without some absolutely comprehensive (to the metropolis, or better still across all of Britian), simple fare paying system.

And like any artic cf DD, wasteful of road space - which in Britian's inner cities can be quite scarce (think of a queue of 5 DD buses at a level crossing, then think of 5 artic buses - how much space is taken from other commercial and service vehicles, not to mention private motorists who are not "evil incarnate" despite the views of some.

And no, haven't been to Leeds for yonks. It's not a case that a City may lack landmark historic buildings, but that even a modern "plaza" is devalued by visual intrusions out-of-character with the design. See my "frog in pot" comment elsewhere this thread.

 

[HSTEd]

Double deckers also drastically increase stop dwell time, especially if they are larger and still have the multiplicity of operators and fares rather than a simple flat fare, smart-card of pre-purchase system.

Unfortunately that is the bus system we have and will have for the forseable future.

I agree, but like all the other advantages the trolleybus has over the diesel/hybrid, the gap will reduce as technology advances.

But technology is never going to advance to the degree that this gap is meaningfully reduced, hybrid/diesel buses inherently have more moving parts and inherently require more maintenance.

You'd need to do this at every stop, in fact arguably it is more needed at the minor stops than the major ones because the occasional trolleybus stopping there will cause several others to queue up behind. Especially so with the dwell time implications of double deckers.

This would only be required on the ultra-intensive "core" section, I make it ~25 stop pairs in that section which would mean a total of 100 line-points which means that you spend about a million pounds to allow buses to pass each other at stops.

On the "legs" of the system where bus intensities are only 6-12bph you probably don't need passing places because the bus dwells will never be sufficient to allow this.
Dwell time on a double-deck is only a major issue if the stop has large amounts of passenger churn, the only stops I know that has this regularly apart from the inner city end of the route would be the UMSU and Owen's Park, the others see on average a handful of people getting on or off at once.

As I said previously I agree Oxford Road is not a sensible corridor for trams, though routes such as the Didsbury Metrolink might take some of the longer-distance passengers off Oxford Road.

Long distance passengers are a rounding error, 90% of the traffic is between Picadilly Gardens and Owen's Park or the University and Didsbury/Parr's Wood.
These are not journeys that would be practical on Metrolink.
The only way to resolve the transports-related issues involves an in-corridor route, cutting around it won't solve anything.

The point at issue is whether trolleybuses would be an improvement. Since in the form you propose they would simply substitute electric traction for diesel hybrid while keeping the same number and size of vehicle, then I suggest the benefit is limited to a small saving in journey time and operating cost, and the reduction of local noise and emissions.

Indeed, and I crunched the numbers on that, assuming the council takes over the running of the buses through a concessionaire then the project makes the council money assuming access to Treasury funding.

There was still rutting at Piccadilly Gardens as I mentioned, where speeds are very low. The issue is more the pressure exerted by the tyres rather than the effects of vehicle speed.

Yes, there is still rutting there and at other bus stops, the question is whether this rutting is actually a serious problem since the suspension of the buses proves adequate at the low speeds involved.
It is a road maintenance issue but not one that threatens to cripple the system in any reasonable amount of time.

A modern transit system would expect to have reliable level boarding for wheelchairs etc, and the dwell time consequences of deploying a ramp would be unacceptable if you are trying to reduce journey times and increase capacity. So the vehicles will have to stop reliably within a lateral tolerance of an inch or two, with or without guidance, and this is the issue that leads to rutting.

But this problem will happen anyway in corridors with intensive bus service so I don't think it is appropriate to ascribe the costs to the trolleybus scheme.



It is typically 1km in a city centre because the route is busier. Trolleybuses carrying the same total number of passengers are likely to need closer-spaced substations because of their increased energy consumption. There is also a tradeoff beween overhead line cross section and substation spacing.

A lot of the discomfort on a bus arises from the reaction of the suspension to an imperfect road surface, or the lateral accelerations from imperfect cornering. These would be the same with a trolleybus unless it was also provided with a solid concrete slab and with guidance respectively

Engine vibration is a significant problem on the corridor, especially with the older buses that operate a large part of the service.
The road surface itself is surprisingly good considering the loading placed upon it, but as you acknowledge there are no non-road options available that people will take seriously (I have myself proposed a 3S cableway once but got laughed at)

I note that some of the quotes in HSTEd's previous post were attributed to me but actually came from someone else.

That is odd.... I will go back and correct this error... I think I must have messed up the quoting system somehow when I attempted to quote two posts at once. Sorry about that.
--- old post above --- --- new post below ---

Crikey HSTed, you seem to be building a Manchester system when the subject was a Leeds system which primarily offered travellers reduced travel time.

Indeed I am, infact you would notice that this is what I was doing in my opening post in this thread.
I am merely interested in NGT to prove that trolleybus electrical equipment can be provided in Britain in a similar cost range to the estimates I have seen for abroad.

And hopefully avoid another Edinburgh trams level screwup.

To suggest people get used to visual intrusion and therefore visual amenity can be discounted is the "frog in a pot of water argument". HSTed, you do spout a load of cobblers at times.

Well the amenity argument could beu sed to attack light rail but noone ever does, it appears to be an argument merely rolled out to attack trolleybuses.

I have already said that a 40km or 1 hour range would be the target for fail-graceful. You might have missed that. In fact, to be a tad more scientific: I would suggest that a statistical analysis of the duration of outages of industrial power supply in the region be undertaken, and the range be set at about the 95%ile of that distribution.

Providing a 40km range for a battery is asking an awful lot.
You are looking at electric car sized batteries, and charging those up repeatedly during operations would be a massive issue.

I have never witnessed even a single-phase outage in central Manchester in all my visits including several night time ones (while living in South Manchester where there were also no significant power outages) and a whole year of living adjacent to the line between Picadilly and Oxford Road.

I have to conclude that loss of power is vanishingly unlikely to the degree that it is pointless planning for it.

And if we must provide provisionf or a power outage, with a fully wired system you could just provide the batteries in the substations where you could use the cheapest possible batery technology since you don't have to worry about carrying them around with you.

I had posted about NaHx batteries - but I was guilty of faulty memory - these are high-temperature, fixed installation batteries. GE have launched their Durathon, with some explanation here: http://www.getransportation.com/ene...ights-durathon-battery-and-ge-innovation.html


If you follow through the links, you will find that GE are combining the NaMh battery with a Lithium battery to obtain an optimum mix of characteristics. The Li battery could also be complemented/replaced in these configurations by Supercaps and KERS.

That is rather impressive performance, but even a 25kWh battery is looking at 500kg using that technology. Since the lithium component would apparently be used primarily to allow load throttling it is likely that this component would be the bulk of the energy storage capacity.

4 times the energy density of Lead Acids is not that impressive when you consider how bad Lead Acids actually are in this application.
I would think you will struggle to fit such a large battery pack into a low floor bus, especially as you will need the electricity supply system regardless.

I am not entirely sure it is really worth it.

 

[radamfi]

And like any artic cf DD, wasteful of road space - which in Britian's inner cities can be quite scarce

Artic buses/trams work fine where proper space is allocated to them. Most city centres on this historic continent have narrow streets, yet nearly all of them run artics quite happily. Amsterdam has streets barely wide enough for a car, yet they run articulated trams down them. Utrecht city centre accommodates three part bendy buses. Manchester runs 4 car trams through its city centre.

 

[starrymarkb]

Unfortunately that is the bus system we have and will have for the forseable future.

Why accept it? Why not lobby to change things for the better?

Not invented here I guess...

 

[edwin_m]

Unfortunately that is the bus system we have and will have for the forseable future.

And it is a major impediment to providing the kind of service that you propose!

But technology is never going to advance to the degree that this gap is meaningfully reduced, hybrid/diesel buses inherently have more moving parts and inherently require more maintenance.

The gap will still be there but ultimately it will only be the diesel engine itself, associated equipment and an alternator. The motors and on-board energy storage will be common with trolleybuses. This may of course mean that the cost of trolleybuses becomes closer to that of diesel buses!

On the "legs" of the system where bus intensities are only 6-12bph you probably don't need passing places because the bus dwells will never be sufficient to allow this.

All these legs will also need OLE, substations etc, which become harder to justify at lower frequencies.

Dwell time on a double-deck is only a major issue if the stop has large amounts of passenger churn, the only stops I know that has this regularly apart from the inner city end of the route would be the UMSU and Owen's Park, the others see on average a handful of people getting on or off at once.

But the inner city is where the flow of vehicles is greatest and the lack of roadspace most critical, and this could therefore limit the frequency on the whole network. No double decker is ever going to match an articulated bus or tram with several sets of double doors, level boarding and a pre-payment fare system.

But this problem [rutting] will happen anyway in corridors with intensive bus service so I don't think it is appropriate to ascribe the costs to the trolleybus scheme.

I agree, it is inherent to the intensive use of a traffic lane by heavy vehicles...

Engine vibration is a significant problem on the corridor, especially with the older buses that operate a large part of the service.

...but by a similar logic you can't use this argument, since your proposal would buy new vehicles then it should be tested against an alternative that buys new buses.

That is odd.... I will go back and correct this error... I think I must have messed up the quoting system somehow when I attempted to quote two posts at once. Sorry about that.

No problem. Not sure I understand that how this works myself!

I have never witnessed even a single-phase outage in central Manchester in all my visits including several night time ones (while living in South Manchester where there were also no significant power outages) and a whole year of living adjacent to the line between Picadilly and Oxford Road.

I have to conclude that loss of power is vanishingly unlikely to the degree that it is pointless planning for it.

Agreed it doesn't seem to be a major problem. In any case traction supply systems are designed to continue working from the substations either side if one substation goes out, so will also tolerate a loss of the supply to one substation due to a local power failure. There is a possible issue with physical damage to the overhead line, which may be more of a problem with trolley poles than pantographs but on the other hand a trolleybus with even a small battery can get round it.

 

[JohnB57]

Now, looking at the issue of inductive power supply, I see these as being restricted to specific locations if they're used at all. Otherwise, a "wireless" trolley sysyem could be charged from short sections of wiring. Where all of these are on guideway, a single-wire AC supply could be possible (but AFAIK untried) - otherwise conventional DC two-wire.

I'd be fascinated to know how a single wire would work in this application, whether AC or DC.

 

[AndyHudds]

The Spen line could only realistically be reconnected with the Healey Mills/Calder Valley line in the Wakefield direction which would offer additional services far too limited to be viable.


The scope for this is quite limited. Up the Colne Valley, the line was slewed in 1979 to allow higher line speeds and this now takes up most of the trackbed on the bends. Reversing this would reduce line speed. To the east of Huddersfield, the trackbed is not uniformly wide enough to re-quadruple so the benefits would again be marginal.


"Wireless" in this context doesn't mean RF. It means "without wires". Of course, your tongue could be firmly in your cheek...

Trolleybus cabling involves two conductor wires so it is a little more intrusive than that for trams. For the same reason, on junctions cabling is quite complex and would require additional switching equipment activated from the cab. No reason to reject trolleybuses but something to consider.

Regarding the Spen Valley line I really don't think that's true, what you say. A curve could be built in the Huddersfield direction, there is plenty of land around there for the curve to be accommodated, with Ravensthorpe station extended with platforms in the Huddersfield/Wakefield direction.

As for the Colne Valley section, yes I know its been slewed to maximise speed, but I just think they could undertake more infrastructure work on the line in the Leeds to Manchester section to ease the current congestion and lack of capacity. More than electrification is needed.

 

[61653 HTAFC]

Regarding the Spen Valley line I really don't think that's true, what you say. A curve could be built in the Huddersfield direction, there is plenty of land around there for the curve to be accommodated, with Ravensthorpe station extended with platforms in the Huddersfield/Wakefield direction.

As for the Colne Valley section, yes I know its been slewed to maximise speed, but I just think they could undertake more infrastructure work on the line in the Leeds to Manchester section to ease the current congestion and lack of capacity. More than electrification is needed.

Realistically, I think the most we can hope for is to relay track in the two disused bores of Standedge tunnel, which would at least allow faster services to overtake stoppers or freights- though fitting the OHLE in the single bores might be a challenge, and I believe one of the disused bores is an evacuation route for the canal tunnel- Fire engines occasionally reverse down there on training exercises I think. Of course it might be possible to relay track in a 'tramway' type configuration that would maintain emergency access but it would add to the cost.

Apologies for the off-topic diversions- to bring us back, does anyone know what the gradient profile is on the proposed trolleybus route?

 

[DW54]

I'd be fascinated to know how a single wire would work in this application, whether AC or DC.

AC: doesn't really require a "neutral" or earth, just a suitable capacitor. However, this could be complemented in a belt-and-braces approach by an "earth strap" (think the sort of "static" strap folk used to attach to their cars). On the guideway section, the straps would align with studs or strips on the surface that are soundly and solidly earthed. This allows a pantograph to be used, reducing complexity and the scale of suspended aerial kit. The voltage could be much higher than 600-750v DC, meaning lighter contact wire and stringers - but heavier insulators near the power poles.

DC: only possible with an underside contact shoe or strap in a guideway section, set at 0vDC (ie earth). As this will be an essential part of the circuit, good contact is absolutely vital.

I'm not aware of either being in use, but am aware of stud contact being used to power well established "wireless" trams in Europe. (Can't recall which City, sorry.) The corollary is that if it's OK to deliver 600vDC that way (and there are objections, I understand), surely earth (0v DC) should be that much more again OK.

There are naysayers on this thread who have tried to hijack it to address Manchester's issues, to seek to tell us that visual intrusion will disappear because we'll get used to it, to tell us that battery technology can't be used because it won't fit under low floor buses, etc.

Let's just clear up the latter. Almost all low floor solutions put the gear that used to be underslung on the roof. Also in smart locations like under driver's position, underneath fixed seats and in other voids not required for passenger accommodation. So light, modest sized batteries can't be used because they can't fit (unless we raise up our eyes and look to the roof.) When the Mercedes Hydrogen cell buses did their "world tour", the design had most of gear on the roof. CNG buses have the compressed gas tanks on the roof.

Anyway, the whole NEED for trolleybuses hangs on their being legally distinct from buses - which is a legal nonsense.

And Leeds would be a heap better off working on the systems that WILL deliver the objective: passenger travel time savings, justifying to residents their use of park'n'ride vs driving to the centre to park. And once the City has implemented the roadway changes, busway(s), signalling and wayside stops that contribute 90+% of the performance, then the project leaders can look at the latest developments on the legal/planning/admin front. If it's still necessary at that stage to make a legal distinction so that the City can control pricing and performance of the operator, then study the state of maturity of all potential types of solution that satisfy the legal criteria. This gives several years more time to work on the legal issues (including a possible legislative solution), as well as time for emergent systems to reach maturity.

These planning, legal and project timing issues haven't been addressed in the thread: just criticisms of anything that is not a conventional fully wired 2-wire DC supplied trolleybus system.

 

[edwin_m]

Presumably the single conductor AC you mention is repeatedly charging and discharging the capacitor and the resulting current flow can power the traction package.

I've not heard of this type of system but I would have thought it would need some form of earthing in case some sort of fault situation raised the potential of the vehicle (asymmetric AC?). However I think rubber tyres are conductive so maybe this could be done by putting metal studs in the road and making sure the HVAC end of things was very well insulated from the bodywork?

The AC wire dropping onto the roof of the vehicle could also be a concern, but less so at high voltages because the fault current would be higher and the service current would be lower so the fault would be easier to detect.

 

[transmanche]

There are naysayers on this thread who have tried to hijack it to address Manchester's issues, to seek to tell us that visual intrusion will disappear because we'll get used to it, to tell us that battery technology can't be used because it won't fit under low floor buses, etc.

I'd just like to pick up on the 'visual intrusion' aspect.

One reason that trams and similar encourage modal shift is because they generate a perception of permanence - something that a conventional bus system cannot provide. So what you call 'visual intrusion', I call evidence of investment in a quality transport system - something that would encourage usage of a trolleybus system.

 

[starrymarkb]

I'm not aware of either being in use, but am aware of stud contact being used to power well established "wireless" trams in Europe. (Can't recall which City, sorry.) The corollary is that if it's OK to deliver 600vDC that way (and there are objections, I understand), surely earth (0v DC) should be that much more again OK.

Are you thinking of APS in Bordeaux, if so it only makes the system live when a tram is completely over the rails?

The Italians also have a system, but being made by AnsaldoBreda it's probably best avoided (even with the proverbial barge pole)

 

[HSTEd]

With regards to these "Durathon" batteries, they are only rated for 0.5C, which means that they must be able to support the power demand for a full 2 hours and will take 8.4 hours to recharge from full discharge.

This makes them terribly badly suited for supply of trolleybus system since you have to be able to supply the full ~200kW value for regular off-wire operation.
Even with a lithium-ion battery buffer they are very badly suited to this operation.

A lithium ion battery would still have to weigh several hundred kilogrammes and would suffer massive cycling issues since you would have to potentially cycle the battery several times a day.

In summary, partially wire trolleybus routes have major problems which is why the route which uses them operationally in Rome has serious problems. (And it is worth noting that the battery powered section is only 10% of the total route length)

And as to the APS system in Bordeaux, it has proven to be a serious operational nightmare for the tramway, which is why it is unlikely to be used in any further expansions of the system and a section of it has apparently been converted to overhead wiring.

And automatic rewiring has proven to be quite problematic and the operational difficulties have to be matched against the supposed "loss of amenity" and capital cost of the extra wire-switches.

 

[34D]

Apologies for the off-topic diversions- to bring us back, does anyone know what the gradient profile is on the proposed trolleybus route?

Nothing notable, most of the route from Lawnswood to the city centre seems to be on a slight incline, but there aren't any hills that will really test it (in the proposed first route).