North Downs line electrification

[59CosG95]

That is already known to be a temporary step in the cascade process. Once the Waterloo extensions are completed the 456s will all be in use on main suburban 10 car services (4+4+2), and the Guildford - Ascot service will by default have to go back to something more suitable, such as 450s.

Ah I see, wasn't aware of that development. Should certainly ease the process of wiring then!

 

[Phil.]

Desiros are dual voltage machines, it would take about 12-18 hours to make each one a fully fledged dual voltage machine, so there are no issues there.

IF they choose 25kV OHLE, then it could be installed for the whole length or just between Wokingham station and Ash station and Shalford Junction to Reigate station, as you'll have to allow a distance to ensure that there's an adequate distance to do a changeover from AC to DC & v.v.

That would not affect any operation of the existing 3rd rail stock, whether it be 450/456 or 458.

@infobleep.

Kent should be included in the plans, as with electrification it opens up the opportunity to extend services to Ashford for international connections, also freight from the Channel Tunnel avoiding London, the only caveat being that they'd need to build a flyover to avoid the necessity to runaround the train.

A curve to link the Reading line directly to the Brighton line should be seen as highly desirable as it again avoids time consuming reversals and any delays due to congestion in the station area.

What is it about Redhill that everyone has it in for? A developing and growing town with an increasing - mostly Croydon/London - commuter base. The London trains have already been thinned out and now you want to cut the Reading/Gatwicks out too. That'll really encourage people to take to the trains. As for a flyover, the same reasons apply. It ain't never gonna happen.
In 2001 the population was about 29,500 In 2014 it had grown to about 36,750 and continues so. Rail companies ignore those figures at their peril.

 

[MarkyT]

As for a flyover, the same reasons apply. It ain't never gonna happen.

That's a double negative! Agreed there would be little point using it to allow passenger traffic to bypass the station, but a flyover would be essential if the Ashford - Redhill - Reading axis was developed as a major continental freight route bypassing London and linking into the GWML and future electric freight spine going north. An extra leg (shown blue in attached image) might be added to allow up trains from Tonbridge to access the up side of the station with reduced Brighton line conflict, also for any notional new Guildford - Tonbridge axis service calling and reversing at Redhill.

 

[HarleyDavidson]

What is it about Redhill that everyone has it in for? A developing and growing town with an increasing - mostly Croydon/London - commuter base. The London trains have already been thinned out and now you want to cut the Reading/Gatwicks out too. That'll really encourage people to take to the trains. As for a flyover, the same reasons apply. It ain't never gonna happen.
In 2001 the population was about 29,500 In 2014 it had grown to about 36,750 and continues so. Rail companies ignore those figures at their peril.

Didn't say every train should miss it, the avoiding curve would be useful for a faster Reading- Gatwick service (Redhill already has plenty of service provision for that), but also for any diversionary traffic should the Brighton main get closed north of Redhill, across to Guildford up to Effingham and Epsom and away.

Depending on the line speed (I'd like to think that it will be improved somewhat) it only takes about 20-25' to get across non stop to Guildford and about 25' to Epsom at line speed.

The flyover to the Tonbridge line would be great for freight and faster services to Tonbridge and Ashford International opening up the journey opportunity of Reading to there and the continent without the hassle of cross London transfers.

 

[infobleep]

What is it about Redhill that everyone has it in for? A developing and growing town with an increasing - mostly Croydon/London - commuter base. The London trains have already been thinned out and now you want to cut the Reading/Gatwicks out too. That'll really encourage people to take to the trains. As for a flyover, the same reasons apply. It ain't never gonna happen.
In 2001 the population was about 29,500 In 2014 it had grown to about 36,750 and continues so. Rail companies ignore those figures at their peril.

The rail companies ignore those figures at their choice.

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

Didn't say every train should miss it, the avoiding curve would be useful for a faster Reading- Gatwick service (Redhill already has plenty of service provision for that), but also for any diversionary traffic should the Brighton main get closed north of Redhill, across to Guildford up to Effingham and Epsom and away.

Depending on the line speed (I'd like to think that it will be improved somewhat) it only takes about 20-25' to get across non stop to Guildford and about 25' to Epsom at line speed.

The flyover to the Tonbridge line would be great for freight and faster services to Tonbridge and Ashford International opening up the journey opportunity of Reading to there and the continent without the hassle of cross London transfers.

Personally I don't think Redhill has plenty of provision for Gatwick. They cut the services didn't they allow faster Southampton ones to avoid it.

I know if the 3 mins past to Reading is cancelled and someone isn't at Gatwick in time for the 52 minutes passed, they will be an hour late to Reading as the 22 minutes passed doesn't connect with the slower Redhill to Reading service.

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[aylesbury]

The line to Redhill must be electrified as it is an important cross country route and as third rail, so trains from Reading can continue southwards without interruption.

This will give new journey opportunities and increase revenue, also third rail means not so much civil engineering and a quicker result.

 

[LBSCR Times]

I know if the 3 mins past to Reading is cancelled and someone isn't at Gatwick in time for the 52 minutes passed, they will be an hour late to Reading as the 22 minutes passed doesn't connect with the slower Redhill to Reading service.

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Or there is the xx.08 TL service from Gatwick during the day, which connects.

Of course GWR also want to operate a half-hourly service to and from Gatwick too.

 

[HowardGWR]

Clearly, direct services to Gatwick or Ashford, from far away, could do with the infrastructure flyover suggested. Just how much time could be gained by an update to the NDL, not just electrificaton but also realignment and signalling, to enable non-stop services from Reading. If Gatwick is allowed to go for a second runway after 2019 when the covenant ends, could we envisage Cardiff /Bristol to Brighton direct services, for instance?

What sort of time e.g. Bristol to Gatwick could be achieved?

 

[SpacePhoenix]

By the time that the North Downs line gets electrified with AC which I assume would be at least a decade before it gets done time things go through like planning it, funding it etc, how close to their absolute end of life will the 455s and 456s be? If they'll be very near their final end of life by then I'd expect new units to possibly be ordered

 

[Philip Phlopp]

By the time that the North Downs line gets electrified with AC which I assume would be at least a decade before it gets done time things go through like planning it, funding it etc, how close to their absolute end of life will the 455s and 456s be? If they'll be very near their final end of life by then I'd expect new units to possibly be ordered

It depends when (and how) the work is done, if it's done, and what other capacity calculations come into the mix.

 

[infobleep]

Or there is the xx.08 TL service from Gatwick during the day, which connects.

Of course GWR also want to operate a half-hourly service to and from Gatwick too.

OK I guess I was travelling in the evening when xx.08 doesn't operate. Either way the next train I could get when I didn't make the xx.52 was the xx.22. It was probably after 6pm I was travelling. Can't remember exactly.

If GWR have additional trains it might be OK, as long as they don't terminate them short at Redhill as well during disruption. May be with more trains running they could avoid terminating one and run its return service stopping at Kass stations to make up time.

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[QueensCurve]

never mind that on the 25Kv railway each 4-car unit is hauling round its own substation/transformer

That is the whole point of AC electrification.

Because the train can carry a transformer, the line voltage can be mush higher. Higher voltage means lower current. Lower current means less heating. Less heating means lower losses. Lower losses means fewer feeder locations.

Much more efficient all round.

 

[Tio Terry]

The line to Redhill must be electrified as it is an important cross country route and as third rail, so trains from Reading can continue southwards without interruption.

This will give new journey opportunities and increase revenue, also third rail means not so much civil engineering and a quicker result.

Not likely to happen. DfT/ORR have stated in the latest Energy TSI that there will be no extension of the 3rd Rail network and any works will be limited to minor renewals and system strengthening for longer/heavier/air-conditioned trains on the existing network.

 

[The Ham]

The line to Redhill must be electrified as it is an important cross country route and as third rail, so trains from Reading can continue southwards without interruption.

This will give new journey opportunities and increase revenue, also third rail means not so much civil engineering and a quicker result.

If XC were to extend a service from Reading, they would much rather the line was OHLE so as to not need duel voltage units (although they would for services beyond Southampton).

 

[Phil.]

That is the whole point of AC electrification.

Because the train can carry a transformer, the line voltage can be mush higher. Higher voltage means lower current. Lower current means less heating. Less heating means lower losses. Lower losses means fewer feeder locations.

Much more efficient all round.

Right up to the point the wind or a defective pantograph brings it down.

 

[TheKnightWho]

Right up to the point the wind or a defective pantograph brings it down.

And 3rd rail has no environmental problems of its own?

Leaving aside leaves and ice, of course, which are quite a bit more common...

 

[Philip Phlopp]

And 3rd rail has no environmental problems of its own?

Leaving aside leaves and ice, of course, which are quite a bit more common...

And fizzy drinks cans.

The reality is delays caused by DC buggering up the signalling system will routinely exceed occasional but more severe delays from a de-wirement.

 

[tsr]

And fizzy drinks cans.

The reality is delays caused by DC buggering up the signalling system will routinely exceed occasional but more severe delays from a de-wirement.

I work every day on DC lines in a really quite busy area of London and the South East. Bar a couple of very specific high-profile incidents caused at least in part by maintenance failings, I cannot think of a single time when a problem caused by everyday failings by or interference from the DC system caused anything like the inconvenience of a dewirement or dewirement precautions for passenger journeys, or for that matter freight. Even the recent issue at Gatwick, something which was something of a complex scenario in an especially awkward location, still allowed 4 out of 7 discrete lines to remain open and fully functional beyond the initial incident being dealt with by the signaller; something which, with the best will in the world, would quite possibly not be remotely viable under many currently-operational OHLE electrification schemes, especially those not of new construction (of which, of course, the 3rd rail system via Gatwick Platforms 1/2/3 isn't). If we look at minor delays due to issues such as track circuit faults, often these delays may impact an initial service badly, but thereafter only a couple of minutes may be lost, depending on linespeeds, calling patterns, signal section lengths and local operating instructions. I have been on lines where only 2 or 3mins were being lost per train due to a signalling problem which later turned out to be partly due to DC electrification, over the course of several hours; in the event of AC system damage, the whole line or at least that section of contact wire would have been out of use for that duration, closing a major commuter route for the whole evening peak. The most problematic signalling issues I come across are 90% of the time those actually found on diesel-only, non-electrified routes...

Indeed, one could argue that, though horrendously inconvenient at times mainly in terms of locations and poor timing, if the DC electrification system almost "self-tests" through the surrounding infrastructure, it all remains far safer to approach during troubleshooting - one only needs to keep a matter of centimetres, rather than multiple metres, away from much DC equipment found "on the ground", unlike AC which requires cumbersome equipment and procedures to so much as approach (which is not to deny both systems have their inherent dangers, of which I am fully aware). In addition, the third-rail system is not prone to having to be rebuilt after damage from poor weather conditions; only the most severe incidents of poor weather will result in third-rail equipment at the scene of an incident being damaged, normally flooding where trains could not run anyway, or icing sufficient not just to cause arcing but also terrible adhesion.

As for your "fizzy drinks cans" comment, I raise you footballs, stray stuff from people's washing lines, balloons, pigeons... you try OHLE on the London Bridge - East Croydon routes and see how you get on...

 

[Philip Phlopp]

I work every day on DC lines in a really quite busy area of London and the South East. Bar a couple of very specific high-profile incidents caused at least in part by maintenance failings, I cannot think of a single time when a problem caused by everyday failings by or interference from the DC system caused anything like the inconvenience of a dewirement or dewirement precautions for passenger journeys, or for that matter freight.

Even the recent issue at Gatwick, something which was something of a complex scenario in an especially awkward location, still allowed 4 out of 7 discrete lines to remain open and fully functional beyond the initial incident being dealt with by the signaller; something which, with the best will in the world, would quite possibly not be remotely viable under many currently-operational OHLE electrification schemes, especially those not of new construction (of which, of course, the 3rd rail system via Gatwick Platforms 1/2/3 isn't).

That's precisely why the existing electrification schemes are being improved, and why the new schemes make use of mechanically independent registration.

Gatwick with a comparable incident - something like an insulator failure - on 25kV OLE with Series 1 or Series 2 systems would have had the same 4 or 5 out of 7 lines still available to all traction once the initial incident had been resolved, with the remaining lines available for diesel traction depending on the intended repair work. It's also highly unlikely that there would have been the same issues with damage to pointwork. Circumstances vary, but it's likely that an issue of this severity could be repaired off-peak and all lines returned to service for evening peak. A dewirement would have the affected line(s) closed overnight, so realistically unlikely to be any more severe and quite possibly less severe to resolve.

If we look at minor delays due to issues such as track circuit faults, often these delays may impact an initial service badly, but thereafter only a couple of minutes may be lost, depending on linespeeds, calling patterns, signal section lengths and local operating instructions. I have been on lines where only 2 or 3mins were being lost per train due to a signalling problem which later turned out to be partly due to DC electrification, over the course of several hours; in the event of AC system damage, the whole line or at least that section of contact wire would have been out of use for that duration, closing a major commuter route for the whole evening peak. The most problematic signalling issues I come across are 90% of the time those actually found on diesel-only, non-electrified routes...

It depends on OLE system employed, there's no doubt Mark 3b with headspans really is bad when it goes wrong, but for a new Series 1 or Series 2 installation, a dewirement will be significantly less disruptive, generating significantly fewer delay minutes. The reliability of the new systems further reduces the frequency of incidents, even if it can do nothing to reduce the severity. 10,000 delay minutes due to a dewirement once every couple of years is still going to be better than 250 delay minutes due to DC third rail failure or DC related signalling issues a few dozen times a year.

Indeed, one could argue that, though horrendously inconvenient at times mainly in terms of locations and poor timing, if the DC electrification system almost "self-tests" through the surrounding infrastructure, it all remains far safer to approach during troubleshooting - one only needs to keep a matter of centimetres, rather than multiple metres, away from much DC equipment found "on the ground", unlike AC which requires cumbersome equipment and procedures to so much as approach (which is not to deny both systems have their inherent dangers, of which I am fully aware). In addition, the third-rail system is not prone to having to be rebuilt after damage from poor weather conditions; only the most severe incidents of poor weather will result in third-rail equipment at the scene of an incident being damaged, normally flooding where trains could not run anyway, or icing sufficient not just to cause arcing but also terrible adhesion.

The ECML electrification isn't good, but we've got reliable electrification infrastructure elsewhere in the country. Saltcoats system is good and the WCML wiring up Shap and Beattock regularly puts up with the levels of wind which blow empty containers clean off wagons.

Third rail also benefits from being installed in areas which generally encounter less severe weather, if it was installed in the same sorts of areas, it would suffer from similar debris issues to OLE.

So yeah, I'd say you're broadly right when it comes to OLE, and if the systems were equal, there wouldn't be much to choose between AC and DC, but when you add in losses, safety, maintenance, speed and the amount of power that can be supplied by 25kV AC, even with the advantages DC has, it's still the vastly inferior overall system.

 

[infobleep]

I work every day on DC lines in a really quite busy area of London and the South East. Bar a couple of very specific high-profile incidents caused at least in part by maintenance failings, I cannot think of a single time when a problem caused by everyday failings by or interference from the DC system caused anything like the inconvenience of a dewirement or dewirement precautions for passenger journeys, or for that matter freight. Even the recent issue at Gatwick, something which was something of a complex scenario in an especially awkward location, still allowed 4 out of 7 discrete lines to remain open and fully functional beyond the initial incident being dealt with by the signaller; something which, with the best will in the world, would quite possibly not be remotely viable under many currently-operational OHLE electrification schemes, especially those not of new construction (of which, of course, the 3rd rail system via Gatwick Platforms 1/2/3 isn't). If we look at minor delays due to issues such as track circuit faults, often these delays may impact an initial service badly, but thereafter only a couple of minutes may be lost, depending on linespeeds, calling patterns, signal section lengths and local operating instructions. I have been on lines where only 2 or 3mins were being lost per train due to a signalling problem which later turned out to be partly due to DC electrification, over the course of several hours; in the event of AC system damage, the whole line or at least that section of contact wire would have been out of use for that duration, closing a major commuter route for the whole evening peak. The most problematic signalling issues I come across are 90% of the time those actually found on diesel-only, non-electrified routes...

Indeed, one could argue that, though horrendously inconvenient at times mainly in terms of locations and poor timing, if the DC electrification system almost "self-tests" through the surrounding infrastructure, it all remains far safer to approach during troubleshooting - one only needs to keep a matter of centimetres, rather than multiple metres, away from much DC equipment found "on the ground", unlike AC which requires cumbersome equipment and procedures to so much as approach (which is not to deny both systems have their inherent dangers, of which I am fully aware). In addition, the third-rail system is not prone to having to be rebuilt after damage from poor weather conditions; only the most severe incidents of poor weather will result in third-rail equipment at the scene of an incident being damaged, normally flooding where trains could not run anyway, or icing sufficient not just to cause arcing but also terrible adhesion.

As for your "fizzy drinks cans" comment, I raise you footballs, stray stuff from people's washing lines, balloons, pigeons... you try OHLE on the London Bridge - East Croydon routes and see how you get on...

Does anyone know how they did get on when London and Brighton South Coast Railway had OHLE?

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[Taunton]

Does anyone know how they did get on when London and Beighton South Coast Railway had OHLE?

The fact that it was given up and changed over to 3rd rail when comparatively new is a bit of a giveaway.

 

[Domh245]

The fact that it was given up and changed over to 3rd rail when comparatively new is a bit of a giveaway.

I thought that was due to direction from the top bosses at the newly formed Southern Railway who had come from the LSWR who had been using the third rail system. IIRC they either wanted to save face and use their system as the superior system, or that the third rail was simply cheaper than the OHLE.

 

[ExRes]

London and Beighton South Coast Railway had OHLE?

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The drivers must have had bloody big route cards

 

[MarkyT]

The fact that it was given up and changed over to 3rd rail when comparatively new is a bit of a giveaway.

This article in Rail Engineer, reporting the IET Railway lecture of Nov 2011 given by Peter Dearman, Head of Network Electrification at Network Rail, reckons the Southern Railway's decision was a mistake.

http://www.railengineer.uk/2011/11/28/electrification-a-critical-analysis/

. . . SR took the decision to standardise on the third rail system. The LBSC overhead system was dismantled and the lines converted.

With the benefit of hindsight this was the wrong decision and the railways of Southern England have had to live with this legacy ever since

.

It is possible the decision was partly swayed by anti German feelings post WW1, as the LBSC system was a very Germanic style system, operating at 6700VAC with a fairly low frequency of 25Hz. This allowed the traction to use series-would 'universal' DC motors with no on-board rectification nor unacceptable destructive levels of commutator flash-over. That approach was very similar to systems being rolled out accross Central Europe and Scandinavia at the time and the main contractor for the original system was AEG of Berlin, although British subcontractors were used extensively.

http://www.bloodandcustard.com/SLAC.html

 

[SpacePhoenix]

For a train heading onto the North Downs Line at the Reading end from Basingstoke, would it need to reverse at Reading?

 

[NSEFAN]

For a train heading onto the North Downs Line at the Reading end from Basingstoke, would it need to reverse at Reading?

Shouldn't need to, there's a link under the GWML that trains could use to access the SW lines from the west.

 

[edwin_m]

I thought that was due to direction from the top bosses at the newly formed Southern Railway who had come from the LSWR who had been using the third rail system. IIRC they either wanted to save face and use their system as the superior system, or that the third rail was simply cheaper than the OHLE.

I've read somewhere that they wanted to have compatibility with the Underground, which then as now could be achieved by adding a fourth rail and bonding it to the running rails.

With hindsight the higher voltage system might have been the better option for the Southern. But I guess only inner suburban operation was envisaged at the time where the power losses at the lower voltage were less of an issue. Either system was probably cheaper to run than steam power on that type of service, so any differences in efficiency may not have been considered important.

Had the Southern gone for the 6.25kV system we might have ended up standardising on German-style 16Hz electrification across the network...

 

[XDM]

The issue of DC versus AC can be simply tested. The minutes lost per AC wire failure are enormously greater than the minutes lost per DC conductor rail failure. It should make the DC armchair converters hang their heads in shame. If there was a proper maintenance regime for the third rail,with ballast & footballs cleared from providing a current flow in wet weather, the power consumption comparisons would be favourable to third rail,specially as every DC 12 car train does not have to drag 10 tons of track bashing transformer up hill & downdale.

 

[NSEFAN]

The issue of DC versus AC can be simply tested. The minutes lost per AC wire failure are enormously greater than the minutes lost per DC conductor rail failure. It should make the DC armchair converters hang their heads in shame.

... and as Philip Phlopp has just pointed out, the incident rate is lower for overhead electrification schemes. Newer OLE is also designed to minimise the fallout from dewirewirement, taking only one line out of service rather than all of them.

If there was a proper maintenance regime for the third rail,with ballast & footballs cleared from providing a current flow in wet weather, the power consumption comparisons would be favourable to third rail,specially as every DC 12 car train does not have to drag 10 tons of track bashing transformer up hill & downdale.

Any system would work better if you could throw more resources at it, but resources are limited (that's why there isn't much appetite for mass DC - AC conversion, but you wouldn't generally build a new heavy rail 3rd rail railway given the benefits of overhead electrification). Given how efficient and compact HV power electronics are these days, I don't think an extra 10 tons on top of the couple of hundred tons for 4 car EMU are much to worry about.

 

[najaB]

If there was a proper maintenance regime for the third rail,with ballast & footballs cleared from providing a current flow in wet weather...

No matter how many times you say it, P=I^2R doesn't change. Losses increase as the square of the current. Lower voltage equals higher current.