Converting Third Rail To Overhead Wiring

[tbtc]

Most modern EMUs have been built to run on both AC and DC lines. Having one system obviously has a few advantages.

Hypothetically, if you were to convert the SWT/ Southern/ South Eastern lines to Overhead wiring, how would you go about it?

 

[Clip]

Buying miles of wire would be a start

 

[atomicdanny]

There are still a lot of stock that doesn't have AC pantographs (ignoring all of the 444s, 450s and electrostars which I assume could be fitted fairly simply? since they have the space for them) including the South Eastern Networkers, the 442s 455s, 456s, 458s?, 460s? and the other stock that i may have forgotten which I believe were designed for 3rd rail only?

 

[yorksrob]

But the real question is why.

The third rail works. Why go to the effort of converting it.

 

[lm321412]

I'm sorry but I wouldn't really see the point of it...

Third Rail is pretty much the standard south of London and works well and effectively. Touchwood there isn't many problems with it and it would be expensive to go to all the trouble to fit OHLE.

Some of the expensive factors would be:

Fitting pantograph's to 3rd rail traction (some don't have the fittings for a pantograph and probably wouldnt be able to be converted, however i'm lead to believe a pantograph would be easy to fit to something such as a 450)

Buying miles & miles & miles of OHLE cables. Money could be spent electrifying lines that are currently ran by Diesel Traction, not putting more electric over electric lines!


It just wouldn't be worth it. Maybe if third-rail was some huge problem that it fails all the time or there are many deaths from it then you could have a case for OHLE (which isn't perfect itself).

 

[yorksrob]

Indeed, better spend the money on:

1 electrifying non-electrified lines

2 re-opening lines.

 

[YorkshireBear]

Agree there are places in dpeserate need of cash for lectrification or reopening or remoddelling etc etc etc so spend it there not electrifying electric lines

 

[O L Leigh]

The cost of buying and fitting pans and transformers to the existing fleet of units is vanishingly small against the cost of re-electrifying thousands and thousands of miles of railway. If it works well enough (even if it is not the most efficient or effective system of electrification) leave it alone.

However, CRE (3rd rail to you) does need to be limited because of it's inefficiencies. I was appalled when I realised that the ELL extension would done using CRE rather than installing OLE on the new extended section and introducing dual-voltage units. This was a completely new railway operating a self-contained service that did not need to continue with such an outdated system of electrification. OK so it's better than diesel, but why couldn't it have been done to the modern standard (itself established over 50 years ago)?

O L Leigh

 

[Polarbear]

I suspect that there would also be clearance issues with overhead wires in the southern area. Some of the loading gauges are a bit tight down there.

Having said that, part of the line from London Victoria (out to Coulsden North) used to be wired in the early part of the 20th century, until the 3rd rail was adopted as a standard mode across all Southern lines. http://en.wikipedia.org/wiki/London,_Brighton_and_South_Coast_Railway#Railway_electrification

When the Bournemenouth main line was being electrified in the 1960's, 25KV AC was seriously considered as opposed to extending the 3rd rail. One of the arguements against at the time, (I think) was the forest of gantries that would have been required at Clapham Junction, (and the cost of said gaintries).

 

[Wyvern]

One wonders if the OHL would be considered visually intrusive, in which case there would also be the cost of planning permission.

 

[swt_passenger]

This was a completely new railway operating a self-contained service that did not need to continue with such an outdated system of electrification.

Self contained?

The alternative view is that it's a northward extension of the existing SR. As they decided to run it to/from West Croydon, Crystal Palace and eventually Clapham Jn on existing third rail. Not sure about the relative mileages, but isn't the majority of the overall LO ELL/SLL network DC?

 

[mickey]

One wonders if the OHL would be considered visually intrusive, in which case there would also be the cost of planning permission.

I doubt it but even if it were it could be pushed through on a green agenda easily enough.

The most likely candidate for introducing wires over 3rd rail is Basingstoke-Southampton for port traffic. Southampton suffers enough from lack of connectivity as it is, and when Felixstowe is properly wired up it will only get worse. Obviously the Oxford line will need doing too, but that shouldn't be too difficult.

Other than that, I agree we should double electrification until the rest of the country has at least one type. However it should definitely be the ultimate aim. Why do you think almost no one else in the world uses it?

 

[MidnightFlyer]

3rd is perfect for the old Southern, and Merseyside, and OHLE will do the mainlines and other urban areas (ie. Manc and Bhm). There's no point in having one standard form, maybe in the early 1900s when electric railways first came to prominance, but now it would cost too much - its not really a problem anyway - trains on a route with both just switch over at one station, like the MKC-South Croydon and FCC Moorgate trains

 

[LE Greys]

Self contained?

The alternative view is that it's a northward extension of the existing SR. As they decided to run it to/from West Croydon, Crystal Palace and eventually Clapham Jn on existing third rail. Not sure about the relative mileages, but isn't the majority of the overall LO ELL/SLL network DC?

Then there's the plan to link through to another d.c. line at Canonbury (assuming they decide to run trains through to Watford Junction one day). It would seem a little bit pointless to change over at Whitechapel only to change over a second time at Canonbury or Camden Road.

One section where they really should re-electrify is Acton Central-Richmond (although I don't know if District Line stock can work under the wires). I'm not entirely certain, but I think it's a.c. all the way from Acton Central to Stratford now (last time I was down there, it was d.c. from Dalston Kingsland to North Woolwich. Another possibility is Harrow-on-the-Hill to Amersham, assuming that they want to do the Chiltern lines one day. This would make a Baker Street-Aylesbury service practical, allowing Chiltern to extend to Milton Keynes or wherever. Finally, anything on the Southern should start at Ashford and work eastwards, linking in with HS1. However, that would seem pointless when they already have an integrated system. They considered re-electrifying Bournemouth-Waterloo when they extended the 3rd rail to Weymouth, but decided against it because it would have been impractical. I suppose we just have to accept what we have.

 

[YorkshireBear]

I thought part of the route to southapmton couldn't be electrified

read it in spetember modern railways.

 

[swt_passenger]

Then there's the plan to link through to another d.c. line at Canonbury (assuming they decide to run trains through to Watford Junction one day). It would seem a little bit pointless to change over at Whitechapel only to change over a second time at Canonbury or Camden Road.

There are no plans to run passenger services through from the ELL beyond Highbury & Islington; the track layout there doesn't allow for it, there is only a single tracked connection (dual voltage) for ECS movements.

Also, there isn't really 'another DC line' at Canonbury. The NLL through Canonbury is now AC only, all the way from Stratford to changeover points near Willesden Jn, and at Acton Central and North Pole. Yes, the southern pair of tracks for the ELL through Canonbury are DC, but only because they are operationally independent of the NLL. I'm certain that they would have been AC too, if the ELLX had been built as an AC railway.

 

[Trog]

Buying miles of wire would be a start

Or 17' high con rail pots.

 

[WatcherZero]

If you wanted to change wait until a complete renewal was required (every 40 odd years or so) and do it then.

 

[Trog]

If you wanted to change wait until a complete renewal was required (every 40 odd years or so) and do it then.

The trouble with that idea is that different sections of line wear out at different rates. I know of some pre-grouping con-rail that is still in running line use. As modern con rail is nearly half as heavy again as this rail, how long would you wait until most of a line needed renewal at once?

 

[Drsatan]

I thought part of the route to southapmton couldn't be electrified

read it in spetember modern railways.

The SWML to Bournemouth was electrified in 1967; the electrification was extended to Weymouth in 1988.

Converting 3rd rail lines to 25kv AC would be very disruptive given that lengthy track possessions would initially be required. However, NR's proposed 'mobile wiring factory' should decrease possession times.

Such disruption would be aggravated by, in some cases, a lack of diversionary routes, meaning that replacement buses would need to operate. When the SWML from Woking to Bournemouth was electrified in 1967, the Mid Hants railway from Winchester to Alton was used as a diversionary route. However, it closed in 1973, and although the Mid Hants Railway runs trains from Alresford to Alton, extending the line to Winchester would be very difficult, if not impossible, as several housing estates encroach on the trackbed and the M3 bisects the trackbed. Additionally, a compulsory purchase order would be required to operate NR trains to Alton, and I can imagine the MHR fighting it, since such an order would undo about 30 years of hard work.

The other problem with electrification of the SWML is gauge clearances inside Popham, Wallers Ash, and Southampton Tunnels. The recent W9 (or 10?) gauge enhancements should mitigate this but clearances to install OHL, and run higher trains (an important consideration if double deck trains are to be introduced.) might not be enough. So this would require yet more disruptive gauge clearance work.

Therefore, to minimise disruption, Redbridge Junction to Salisbury and Basingstoke via the Laverstock Loop should be electrified at 25kv AC. This would allow SWML services to be diverted while conversion work on the SWML takes place. Electrification of the above lines would not be as disruptive due to the lower traffic flows. If Romsey - Eastleigh were electrified, then Salisbury 'Circular' services to Romsey could go to EMU operation (probably with 450s modified to run on 3rd rail and OHL), allowing 158s to be cascaded elsewhere, possibly to lengthen West of England line trains to Exeter St Davids pending electrification. Electrifying Basingstoke - Salisbury would allow Waterloo - Salisbury stopping services to be turned over to EMU operation.

Finally, to avoid having to reverse all trains at Southampton Central, I suggest that the 'Redbridge chord', proposed by the LSWR and linking the Salisbury and Bournemouth lines, should be built. Building the chord would require the reconstruction of the bridge carrying the A35, although given the strategic value of the chord, the reconstruction of the bridge could well be justified in those circumstances.

 

[MidnightFlyer]

Whenever a line gets electrified, it'll be whatever fits into the area, like Liv-Manc will be overhead, and Marshlink would be third. If Ormskirk-Preston is ever an extension of Merseyrail, Farrington Lane Jn (the junction for Ormskirk at Preston), it'll be both

 

[Lampshade]

Whenever a line gets electrified, it'll be whatever fits into the area, like Liv-Manc will be overhead, and Marshlink would be third. If Ormskirk-Preston is ever an extension of Merseyrail, Farrington Lane Jn (the Ormskirk jn at PRE) will be both

That would be Farington Curve Jn

 

[swt_passenger]

Converting 3rd rail lines to 25kv AC would be very disruptive given that lengthy track possessions would initially be required.

But there's no likelihood whatsoever of any third rail being lifted to be replaced by OHLE. There's £millions being spent on new DC substation installations as we speak, all over the SR. That'll probably extend the life of the system 30 years or so...

 

[MidnightFlyer]

That would be Farington Curve Jn

indeed it is, cant believe I didnt know that and its only 8 miles away

 

[Drsatan]

But there's no likelihood whatsoever of any third rail being lifted to be replaced by OHLE. There's £millions being spent on new DC substation installations as we speak, all over the SR. That'll probably extend the life of the system 30 years or so...

Nonetheless, when more routes are electrified, re-electrifying 3rd rail routes at 25kv AC would eliminate the requirement for dual voltage motive power. This would include electrifying Basingstoke - Reading.

Besides, will this upgrading of the 3rd rail power supply on the SR allow Desiros to operate at full throttle. The previous power supply upgrade allows Desiros to only run at 65% power.

 

[tbtc]

The reason I created this thread is that we are told that no "major" Third Rail electrification will be allowed in future (beyond "infills")...

...so, hypoothetically, if Basingstoke to Exeter is electrified that'd be too "major" to be Third Rail and have to be wired. Okay, this means EMUs switch over at Basingstoke, in the way that they do on the North London Line etc. But what if, one day, the Third Rail stretches needed replacing? Have any lines been converted from one type of electrification to the other?

(or even, have any lines been unelectrified?)

 

[yorksrob]

The reason I created this thread is that we are told that no "major" Third Rail electrification will be allowed in future (beyond "infills")...

...so, hypoothetically, if Basingstoke to Exeter is electrified that'd be too "major" to be Third Rail and have to be wired. Okay, this means EMUs switch over at Basingstoke, in the way that they do on the North London Line etc. But what if, one day, the Third Rail stretches needed replacing? Have any lines been converted from one type of electrification to the other?

(or even, have any lines been unelectrified?)

Funnily enough, a chunk of the North London line which used to be third rail was switched to overhead quite recently. Also, a large part of the Tyneside Metro was third rail then de-electrified in the 1960's. Some of their slammers were inherited by the Southern Region.

 

[142094]

I'm not too sure of the reasoning behind the de-electrification on Tyneside, certainly from what I've read/been told services went downhill with the switchover to diesel. Would be great to have some of the routes still around and still 3rd rail.

 

[LE Greys]

There are no plans to run passenger services through from the ELL beyond Highbury & Islington; the track layout there doesn't allow for it, there is only a single tracked connection (dual voltage) for ECS movements.

Also, there isn't really 'another DC line' at Canonbury. The NLL through Canonbury is now AC only, all the way from Stratford to changeover points near Willesden Jn, and at Acton Central and North Pole. Yes, the southern pair of tracks for the ELL through Canonbury are DC, but only because they are operationally independent of the NLL. I'm certain that they would have been AC too, if the ELLX had been built as an AC railway.

Funnily enough, a chunk of the North London line which used to be third rail was switched to overhead quite recently. Also, a large part of the Tyneside Metro was third rail then de-electrified in the 1960's. Some of their slammers were inherited by the Southern Region.

Now I've heard about this, I'm going to have a look at it fairly soon. Partly to see if there is any way to get trains from Highbury & Islington to South Hampstead without it becoming an operational nightmare.

I'm not too sure of the reasoning behind the de-electrification on Tyneside, certainly from what I've read/been told services went downhill with the switchover to diesel. Would be great to have some of the routes still around and still 3rd rail.

Many are still around, under the name "Tyne & Wear Metro". It's funny to compare the grand North Eastern stations on the Tynemouth loop with the modern shacks on the airport branch (although I think that has a heavy-rail origin as well).

 

[swt_passenger]

Now I've heard about this, I'm going to have a look at it fairly soon. Partly to see if there is any way to get trains from Highbury & Islington to South Hampstead without it becoming an operational nightmare.

The operational nightmare is Camden Road West Junction. Even if the NLR improvements had been as originally planned 3 years ago, ie with the four tracking through Camden Rd station, without property demolition there is a two track pinch point at the junction. As can be seen by the operational plans for the NLL from May 2011 they can only run 6 tph all day, and 8 tph in the peaks (because there is a planned gap in the freight traffic). That is the line's maximum signalled capacity.

Between Camden Rd and Highbury the four tracks have been paired by direction but are to be operationally used as longer freight loops. The postponed four tracking through Camden Rd provided an additional facility, of a central turnback platform for the Stratford - Camden shuttle to run all day, but no major capacity increase for LO, other than the 8 tph service all day

Any extension of ELL services to the west would immediately exceed line capacity (unless NLL trains were removed), and introduce flat crossings of ELL eastbound and NLL westbound trains. Such a timetable cannot be pathed.

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

Nonetheless, when more routes are electrified, re-electrifying 3rd rail routes at 25kv AC would eliminate the requirement for dual voltage motive power. This would include electrifying Basingstoke - Reading.

Dual voltage power doesn't need to be eliminated though. By the nature of their onboard electronics, there are no pure AC EMUs anymore. They all have a 'DC link' between the transformer rectifier and the traction converter. This makes DC pickup a relatively low cost add on capability.

Besides, will this upgrading of the 3rd rail power supply on the SR allow Desiros to operate at full throttle. The previous power supply upgrade allows Desiros to only run at 65% power.

I don't think so, it is aimed at capacity (frequency or train strengthening) rather than out and out speed. NR's CP4 plans generally refer to it being driven by train lengthening, in fact route 3 SWML explicitly includes:

rolling stock and the new configurations will be operating on existing power levels;
no specific requirement to improvement journey times or rolling stock performance;