222 ohle

[YorkshireBear]

If they were converted, would there be any performance benefits? Or the fact its a conversion does that remove the usual performance advantages of EMU's over DMU's?

 

[EWS 58038]

If they were converted, would there be any performance benefits? Or the fact its a conversion does that remove the usual performance advantages of EMU's over DMU's?

You don't need to convert anything on that train actually. it's a normal electric train already which has an onboard electric powerplant (using diesel) to feed the electric engines. Adding a coach with OHLE equipment will increase the capacity and perhaps the train might accelerate a bit faster.

 

[rail-britain]

Adding a coach with OHLE equipment will increase the capacity and perhaps the train might accelerate a bit faster

The capacity won't really increase, as there are a mix of 4, 5, and 7 coach units
Adding a pantograph car would allow the shorter sets to be increased to 6 coaches and the longer sets also reduced to 6 coaches

There would be virtually no difference in performance as the diesel engine operates an electrical generator, and with an electrical source the only weight advantage would be a possible reduction in the amount of diesel fuel required to be carried (the unit would probably retain at least 1/4 just in case required)

 

[YorkshireBear]

Thank you

is it the same case with voyagers?

 

[EWS 58038]

Thank you

is it the same case with voyagers?

Well, it's the same train type/family for 95% so I don't see why the Voyagers should be any different.

Doesn't this all sound a bit like a cheap solution for the Bi-Mode IEP?

 

[ainsworth74]

Doesn't this all sound a bit like a cheap solution for the Bi-Mode IEP?

Well it would be nice to see something official from Bombardier saying they can actually do it, and for roughly x amount of £££. But otherwise yes! Of course it would require to much common sense for the Dft to pursue seriously. :roll:

 

[YorkshireBear]

it does seem basically a cheap version, but that is exactly what they need right now, on another note. I seem to recall voyagers only need 3 of 5 engines to keep to time, by this logic couldnt they add another unpowered carriage use 4 out of 5 ( 4 out of 6 coachs) with no effect to performance ( if anything improved ) wouldnt this be actually very cheap?

 

[rail-britain]

I seem to recall voyagers only need 3 of 5 engines to keep to time

I was on such a service last year, which was losing time throughout, and on climbing Beattock it was clear it needed at least four engines :
http://www.rail-britain.co.uk/wordpress/?page_id=46
13:53 Preston - Haymarket
Operated by Virgin Trains
Reservation Coach E Seat 20
Seat used Coach E Seat 24
Shortly after boarding I placed an order for the Ham sandwich with tea
There was one further service of drinks after Penrith and another after Carlisle
The late running was due to this train only having three of the five engines fully working
This service was operated by 221113
This service arrived in Haymarket at 16:38, 23 minutes late

Just by luck my next service was 5 minutes late, so made my connection
16:38 Haymarket - Inverness
--- old post above --- --- new post below ---

is it the same case with voyagers?

The Voyagers can also be extended with a pantograph coach
The next issue there is this would increase the size of the trains
Equally, the diesel engines would not be required most of the time (on West Coast) and so would be "dead weight"
However, on Cross Country there would also be some benefit, between Glasgow / Edinburgh and York / Leeds / Doncaster

 

[ukrob]

You don't need to convert anything on that train actually. it's a normal electric train already which has an onboard electric powerplant (using diesel) to feed the electric engines. Adding a coach with OHLE equipment will increase the capacity and perhaps the train might accelerate a bit faster.

The capacity won't really increase, as there are a mix of 4, 5, and 7 coach units
Adding a pantograph car would allow the shorter sets to be increased to 6 coaches and the longer sets also reduced to 6 coaches

It doesn't matter how you to try to dress it up, adding another coach WILL increase capacity. Where on earth have you got the idea about REMOVING a coach to add a pantograph from?

 

[rail-britain]

It doesn't matter how you to try to dress it up, adding another coach WILL increase capacity. Where on earth have you got the idea about REMOVING a coach to add a pantograph from?

Make all the Class 222 units the "same length", so some sets would gain both a pantograph coach and one or two coaches (from below)
Whilst the current 7 coach trains would lose two coaches and gain a pantograph coach
It is one thing the units currently come in for criticism for is that the 4 coach trains just don't have enough capacity
Ironically, the short sets are used on stopping services and the longer sets on express services; that doesn't really make sense if longer trains are needed
I made a few journeys on the express services and these could easily be the shorter sets

 

[ukrob]

So your entire statement was based on an idea you had rather than what would actually happen - makes sense now.

You are still categorically wrong to say that capacity would not increase by adding an extra coach.

 

[rail-britain]

You are still categorically wrong to say that capacity would not increase by adding an extra coach

Capacity won't increase in real terms; in effect all the sets become the same capacity
Most TOCs are experiencing increases in passenger numbers and so capacity is decreasing in real terms, as such they are increasing fares in order to manage capacity

Even a basic example like the West Coast Voyagers, increasing these by one pantograph coach increases the capacity of the unit, but for the route the capacity actually decreases in real terms
It is similar with the Pendolinos, the trains will be able to carry more passengers, but the capacity on the route is decreasing

 

[ukrob]

Capacity won't increase in real terms; in effect all the sets become the same capacity
Most TOCs are experiencing increases in passenger numbers and so capacity is decreasing in real terms, as such they are increasing fares in order to manage capacity

Even a basic example like the West Coast Voyagers, increasing these by one pantograph coach increases the capacity of the unit, but for the route the capacity actually decreases in real terms
It is similar with the Pendolinos, the trains will be able to carry more passengers, but the capacity on the route is decreasing

:roll:

Adding an extra carriage into any unit immediately increases capacity unless the frequency is cut, or another carriage is removed from a unit operating the same route.

Seeing as removing carriages is your idea and your idea alone, an idea which nobody with any influence has ever mentioned, then I can safely say that capacity would be increased.

We don't need 'basic examples' to see that. Especially one which states adding a carriage whilst removing none decreases capacity 'in real terms'.

 

[The Planner]

Even a basic example like the West Coast Voyagers, increasing these by one pantograph coach increases the capacity of the unit, but for the route the capacity actually decreases in real terms
It is similar with the Pendolinos, the trains will be able to carry more passengers, but the capacity on the route is decreasing

I'm struggling with that one. How is the capacity decreasing on the route ??

 

[Fincra5]

I'm struggling with that one. How is the capacity decreasing on the route ??

Perhaps how many trains can be run within time of each other, but how would 11 cars of pendolino reduce capacity on a route?

 

[ukrob]

Perhaps how many trains can be run within time of each other, but how would 11 cars of pendolino reduce capacity on a route?

Or, more likely, rail-britain is out of his depth again and will probably not be seen in this thread any more as usually happens when questions about his nonsensical statements are asked.

 

[rail-britain]

Or, more likely, rail-britain is out of his depth again and will probably not be seen in this thread any more as usually happens when questions about his nonsensical statements are asked.

I've answered the question
Unit capacity increases, but route capacity decreases
Information is available based on passenger figures since 2005
However passenger numbers are apparently falling...

 

[ukrob]

I've answered the question
Unit capacity increases, but route capacity decreases
Information is available based on passenger figures since 2005
However passenger numbers are apparently falling...

You haven't answered.

To clarify, here is the question:

How does capacity decrease when an extra carriage is added and non are taken away?

Passenger figures have nothing whatsoever to do with it, total red herring.

 

[The Planner]

I still fail to see how route capacity decreases ?? Will the extra 48 metres of a Pendo suddenly cause huge delays on the WCML ?? I just dont get it

 

[Lampshade]

So when units are strengthened to 2x221 (happens sometimes on Glasgow/Edinburgh services), that's caused the capacity of the route to decrease? :?

Am I missing something here?

 

[route:oxford]

I still fail to see how route capacity decreases ?? Will the extra 48 metres of a Pendo suddenly cause huge delays on the WCML ?? I just dont get it

125mph = 55.9 metres per second.

It will take an extra 0.86 seconds for a train lengthened by 48 metres to clear a section.

It's unlikely that the timetabling is so tight that 0.86 seconds will make a significant difference.

 

[rail-britain]

Train (unit) capacity increases
Passenger numbers increase
Therefore capacity decreases in real terms

By the time such rolling stock has entered service there is in effect a decrease in capacity

Take the Class 390 as an example
These will be increasing by two coaches
However passenger numbers will have increased by 22% since the coaches were ordered in 2008 and enter service in 2012
More passengers, less seats

If you think that is bad, ScotRail have some really worrying figures produced from the latest Audit Scotland report
If the passenger numbers continue to increase then 8 car trains will be required between Kilmarnock and Glasgow by 2015

 

[ukrob]

Train (unit) capacity increases
Passenger numbers increase
Therefore capacity decreases in real terms

By the time such rolling stock has entered service there is in effect a decrease in capacity

Take the Class 390 as an example
These will be increasing by two coaches
However passenger numbers will have increased by 22% since the coaches were ordered in 2008 and enter service in 2012
More passengers, less seats

I understand what you are getting at, however you are fundamentally wrong.

Adding carriages increase capacity - there is simply nothing more to it.

It doesn't matter if passenger numbers have gone up ten thousand percent - the capacity has still increased by adding more carriages.

 

[O L Leigh]

Adding a coach with OHLE equipment will increase the capacity and perhaps the train might accelerate a bit faster.

Er, did you do physics at school?

Adding a trailer coach for the pantograph, transformer and traction control electronics adds weight to the overall formation without adding any power which will make the performance worse. No amount of short-fuelling is going to make up for this extra weight, especially when the trailer fills up with punters.

I am vehemently opposed to electro-diesel bi-mode trains because they reduce the case for rail electrification, and we really need to be electrifying more routes in order that rail remains a viable and green transport solution. Besides, a bi-mode (D)EMU makes for a very poor electric train because of all the dead weight they would be required to tote around. It would be a far better idea to complete the electrification of the MML and replace EMT's mainline stock with a new build of electric train so that the HST's and Meridians could be cascaded elsewhere.

As for the wider question covering Voyagers, I still believe that this is a pointless folly. I have no figures to back this up (but then nor does anyone else, but that hasn't prevented some pretty bold claims), but I would suspect that any energy saved from running in electric mode would be lost in the additional energy required to shift the unpowered pantograph trailer away from the wires. In fact, it could turn out to be a MORE expensive solution. Pending an expansion of electrified routes, the best answer would be to have a mixed fleet of diesel and electric trains with passengers just having to accept that they're going to have to swap from one type to the other at locations such as BNS rather than having through services on the one train.

O L Leigh

 

[mallard]

Er, did you do physics at school?

Adding a trailer coach for the pantograph, transformer and traction control electronics adds weight to the overall formation without adding any power which will make the performance worse. No amount of short-fuelling is going to make up for this extra weight, especially when the trailer fills up with punters.

That's assuming that the pantograph coach is a trailer... No reason why it couldn't have traction motors. It would probably be dead weight under diesel power (unless there is enough spare power from the generators on the other coaches), but it could pull its own weight under the wires.

Besides, a bi-mode (D)EMU makes for a very poor electric train because of all the dead weight they would be required to tote around.

I wonder how the weight of the diesel equipment compares on a 222 to the weight of tilt equipment on a 390? They've been criticised for their high weight-to-passenger-capacity ratio...

As for the wider question covering Voyagers, I still believe that this is a pointless folly. I have no figures to back this up (but then nor does anyone else, but that hasn't prevented some pretty bold claims), but I would suspect that any energy saved from running in electric mode would be lost in the additional energy required to shift the unpowered pantograph trailer away from the wires. In fact, it could turn out to be a MORE expensive solution.

I doubt the Supervoyagers on BHM-Scotland services would spend much time having to shift additional weight outside the wires... For XC services you may well have a point, although if they could be fitted with CRE shoes then the Manchester-Bournemouth services would have a good electric to diesel ratio...

 

[O L Leigh]

Powering the pantograph coach just requires even more power. Either the train is toting around a dead-weight in the form of a trailer or it's now having to provide power for yet more traction motors and burning more fuel into the bargain. Neither solution represents a "win" as both options are as inefficient as each other.

In any case, it would seem that each car's traction equipment is a stand-alone system and that all the engines combined are not generating a common traction supply to be shared among the traction motors spread throughout the train. Powering a set of traction motors on a car that has no generator set of it's own would require a massive rewire of the entire train based around a completely new set of operating principles.

In fact, I'm still reeling from the fact that the Voyager family has an engine and generator set under each coach rather than one big engine and generator for the entire set like the Cl210's and their forebears on the Southern. In what universe was this considered a good idea?

O L Leigh

 

[mallard]

In any case, it would seem that each car's traction equipment is a stand-alone system and that all the engines combined are not generating a common traction supply to be shared among the traction motors spread throughout the train.

As I understand it, that is true for the 220/221 Voyagers, but the 222 Meridians do have a power bus, something to do with the original specified 9-car formations not requiring a full 6750hp, which may support the idea that there is enough "spare power" to add an a non-generating coach to the formation...

In fact, I'm still reeling from the fact that the Voyager family has an engine and generator set under each coach rather than one big engine and generator for the entire set like the Cl210's and their forebears on the Southern. In what universe was this considered a good idea?

Probably something to do with length vs. passenger capacity. HSTs currently stop at platforms that are only long enough for 4 car trains which means only 3 carriages when you include the PC (plus the frontmost door of the 4th, since HSTs lack SDO...). This is a rather awkward for an 8+2 HST, but not so bad for a 5 or 7 car Meridian... Although, a dedicated power car would be a better idea IMHO if this weren't an issue.

 

[O L Leigh]

As I understand it, that is true for the 220/221 Voyagers, but the 222 Meridians do have a power bus, something to do with the original specified 9-car formations not requiring a full 6750hp, which may support the idea that there is enough "spare power" to add an a non-generating coach to the formation.

Powering motors on a non-generating vehicle would require a power bus, but the issue is still clouded.

This isn't a question of "spare power" but of how the power is used. As I hinted at the start, adding a non-generating car adds weight (more if it's not a trailer). Whether or not it has it's own traction motors, the power is still coming from the power produced by the generator set. What we're talking about here is bald bhp/ton ratios and what that would mean for fuel consumption.

Even if a bi-mode (D)EMU could be designed from scratch I would still oppose the idea. What we need is a proper programme of rail electrification that provides more long distance trunk routes and feeder services running under the wires. If trains running under the wires really have to be electric then let them be proper electric trains in order to run with maximum efficiency. If it means a change of train at Birmingham or elsewhere then so be it.

O L Leigh

 

[dave59]

Powering motors on a non-generating vehicle would require a power bus, but the issue is still clouded.

Even if a bi-mode (D)EMU could be designed from scratch I would still oppose the idea. What we need is a proper programme of rail electrification that provides more long distance trunk routes and feeder services running under the wires. If trains running under the wires really have to be electric then let them be proper electric trains in order to run with maximum efficiency. If it means a change of train at Birmingham or elsewhere then so be it.

O L Leigh

Agree 100%. But this is Britain. An integrated network with connections that work (as suggested in the Foster report as an alternative to the bi-mode IEP) can only happen properly with a nationalised system. Electrification will be slow to happen and piecemeal. So we are left with the bi-mode to at least use mains power/regenerative braking where it exists. This will encourage rather than discourage further wiring as operators discover the reduced diesel maintenance requirements and passengers the peace and quiet on offer under the wires. I agree that pure electric trains should absolutely be used wherever possible (Midlands-Scotland for e.g) and there seems no concerted industry effort to even do that! For XC and MML a bi-mode 22X would be significantly better than the pure diesels of today offering improved capacity and a better passenger environment. It's not ideal but offers a sensible interim solution to maintain the through service passengers expect as electrification (hopefully)expands.

 

[DaveNewcastle]

You don't need to convert anything on that train actually. it's a normal electric train already which has an onboard electric powerplant (using diesel) to feed the electric engines.

No.
And I don't know what an "electric engine" is.

There is a vast difference between an electro-diesel loco (or trainset) and an electric loco (or trainset).

The diesel-powered variant places a driver-initiated demand on the fuel burning engines to power the generator(s) so that they can provide the necessary current to meet that demand at the axle motors; a demand which is subject to continuous change. The generator(s) are connected directly to the traction motors (some current going to power hotel services and other utilities of course), so that the control of fuel to the engine is related to the power at the wheels.
The OHLE variant is constantly connected to a high voltage source, so the task faced by the loco/train designer is how to regulate the amount of that (almost constant) voltage is passed to the traction motors - clearly, for much of the time, that voltage must be cut or diverted through alternative loads to reduce the power at the axle motors. Control of these diversions is related to the power at the wheels.

They are quite different engineering systems. The posts on here about a common power bus partly acknowledge these differences, but still overlook some of these fundamental design and engineering differences. Reading some of the posts on here you'd think that electric locos (such as the Cl 91) only had a piece of wire in them (from panto to motors)!