Should third rail be considered again for future electrification projects?

[Gareth]

Merseyrail has apparently ~75 miles of 3rd rail, only 6.5 miles of which are underground. London Underground has about 250 of 4th rail, heaven knows how much of which is underground, but it's a lot more than 6.5 miles. Merseyrail also uses standard-sized NR trains, London Underground does not, for the most part. If we can do away with any ground-level electrified rails, we probably should. It's a lot more feasible to do that in Liverpool than London. Merseyrail is also getting battery trains, which make things more feasible - London Underground does not have these.

Sorry, but so what? London Underground is larger than Merseyrail but that doesn't make Merseyrail a small "island" or make wholesale conversion of its propulsion system a routine operation. I don't see what relevance the loading gauge has, nor do I forsee batteries being able to power trains over anywhere near the entire network for many years yet.

 

[Bletchleyite]

How would you go about converting Merseyrail to bottom contact?

Same way they did the platform heights - close a bit at a time and replace it, and swap the shoes on the stock as necessary. This would require some thought as to how to outstation trains that couldn't reach Kirkdale for a period. Though if the systems weren't incompatible (I'm not sure if they are or not) you could look to fit dual shoegear which would make it a lot easier.

 

[O L Leigh]

Rather than me trying to explain the process it's probably better if you read the guidance notes contained within the following:-

Thank you. I’ll read and digest that a bit later if I may.

Pedantically, London Underground is not and never has been third rail.

Pedantically, yes it has. I believe the core of what is now the Central Line was three rail with a central conductor rail.

 

[Gareth]

Same way they did the platform heights - close a bit at a time and replace it, and swap the shoes on the stock as necessary. This would require some thought as to how to outstation trains that couldn't reach Kirkdale for a period. Though if the systems weren't incompatible (I'm not sure if they are or not) you could look to fit dual shoegear which would make it a lot easier.

I think dual shoegear would be the only acceptable way. Interesting, that this doesn't seem to be a consideration for the Skelmersdale extension, if top contact is the big problem that some insist it is.

 

[Bletchleyite]

I think dual shoegear would be the only acceptable way. Interesting, that this doesn't seem to be a consideration for the Skelmersdale extension, if top contact is such a big problem that some insist it is.

Skem is proposed to be battery, not third rail. Headbolt Lane isn't going to get third rail! The 3 (?) Kirkby diagrams will be battery units.

 

[Gareth]

Well, let's hope that works out.

 

[Wolfie]

Pedantically, yes it has. I believe the core of what is now the Central Line was three rail with a central conductor rail.

Potentially very interesting, TY. Any sources for that, l'd like to read more.

 

[HSTEd]

Same way they did the platform heights - close a bit at a time and replace it, and swap the shoes on the stock as necessary. This would require some thought as to how to outstation trains that couldn't reach Kirkdale for a period. Though if the systems weren't incompatible (I'm not sure if they are or not) you could look to fit dual shoegear which would make it a lot easier.

I can't think of any obvious reason you couldn't make a retractable bottom contact third rail shoe - just as they make retractable top contact shoes. Dual voltage third rail/overhead multiple units are used in the US with bottom contact rails (Metro North I believe).

There was a report (T950) that talked about the loading gauge issues that might arise from conversion to bottom contact - but that report is now buried behind a paywall (Thanks RSSB!) so I can't dig it out.

 

[O L Leigh]

Potentially very interesting, TY. Any sources for that, l'd like to read more.

I’m unable to give chapter and verse at the moment, but I was reading up on old LU stock on Wikipedia the other evening. I believe it was the old gate stock that was arranged this way but, with the absorption into London Transport and the advent of 1920 Standard Stock, the system was converted to 4 rail operation.

 

[Wolfie]

I’m unable to give chapter and verse at the moment, but I was reading up on old LU stock on Wikipedia the other evening. I believe it was the old gate stock that was arranged this way but, with the absorption into London Transport and the advent of 1920 Standard Stock, the system was converted to 4 rail operation.

TY

 

[Ken H]

Potentially very interesting, TY. Any sources for that, l'd like to read more.

I have somewhere a book - The Story of London Underground published by LT in the 60's. I also have a set of pamphlet type books - one for each line, Northern, Piccadilly, Central, District, Bakerloo which went into more detail for those lines. I remember the central 3rd rail for the Central London Railway(CLR). The CLR also had small tunnels that needed to be enlarged to fit 'Standard' stock.

 

[O L Leigh]

TY

MW

 

[Gareth]

WTF?

 

[O L Leigh]

TY = Thank you
MW = Most Welcome
WTF = Wash your mouth out with soap and water

 

[Ken H]

I’m unable to give chapter and verse at the moment, but I was reading up on old LU stock on Wikipedia the other evening. I believe it was the old gate stock that was arranged this way but, with the absorption into London Transport and the advent of 1920 Standard Stock, the system was converted to 4 rail operation.

CLR started with locomotives. They suffered with vibration to the buildings above. I think there were issues with having the traction motor coils wound direct onto the axles, so the unsprung weight was huge. Multiple units solved the issue. I assume the motors were axle hung.
Remember 'gate stock' needed a guard to each gate, so a train crew of 6 or 7 was necessary. Conversion to powered doors must have given a huge saving in staff costs.

Link to pic of CLR train with locomotive - https://3.bp.blogspot.com/-24Jyl51e.../s1600/Screen-Shot-2018-07-22-at-13.07.04.jpg

 

[Gareth]

LOL

 

[Wolfie]

I have somewhere a book - The Story of London Underground published by LT in the 60's. I also have a set of pamphlet type books - one for each line, Northern, Piccadilly, Central, District, Bakerloo which went into more detail for those lines. I remember the central 3rd rail for the Central London Railway(CLR). The CLR also had small tunnels that needed to be enlarged to fit 'Standard' stock.

TY

== Doublepost prevention - post automatically merged: 6 Dec 2021 ==

CLR started with locomotives. They suffered with vibration to the buildings above. I think there were issues with having the traction motor coils wound direct onto the axles, so the unsprung weight was huge. Multiple units solved the issue. I assume the motors were axle hung.
Remember 'gate stock' needed a guard to each gate, so a train crew of 6 or 7 was necessary. Conversion to powered doors must have given a huge saving in staff costs.

Link to pic of CLR train with locomotive - https://3.bp.blogspot.com/-24Jyl51e.../s1600/Screen-Shot-2018-07-22-at-13.07.04.jpg

Interesting.

 

[mr_jrt]

Sorry, but so what? London Underground is larger than Merseyrail but that doesn't make Merseyrail a small "island" or make wholesale conversion of its propulsion system a routine operation. I don't see what relevance the loading gauge has, nor do I forsee batteries being able to power trains over anywhere near the entire network for many years yet.

Of course it makes it an island. A medium-sized one, but still an island. You think it's going to be extended to Wigan, Preston or Warrington?

The relevance of the loading gauge is that a tube train isn't going to have room for an AC transformer, nor a set of batteries. NR stock can, and in Merseyrail's case, will. Standardisation reduces costs and gives greater efficiencies. To that end, once Merseyrail has dual voltage battery stock it makes sense to convert the extremities to OHLE where they interact with nearby AC routes, which whilst currently would just be the southern end of the northern line, will hopefully over the next 20 years include all three lines north of Liverpool, the line from Wigan to Southport, and the CLC route as well.

...and I very clearly wasn't suggesting that the entire network would be powered by batteries. You get more power with overhead, which lends itself to discontinuous electrification recharging onboard batteries far more practically than 3rd rail would. Having 3rd rail through the loop is fine whilst there so much of it elsewhere, but when the loop is all that's left you may as well decommission it and just use the batteries.

 

[Gareth]

Then London Underground is an island also.

All hypothetical anyway. Mass conversion of Merseyrail to 25kv AC isn't going to happen anytime soon and most likely never. Sure, it means no Pendolinos on the loop (someone seriously suggested that a few years ago) but most of us can live with that.

 

[mr_jrt]

Well, London Underground *is* connected to the southern region's network, and London Overground's as well, so perhaps not.

 

[Gareth]

Good stuff. Covert it all. Convert it all now.

 

[507020]

Then London Underground is an island also.

All hypothetical anyway. Mass conversion of Merseyrail to 25kv AC isn't going to happen anytime soon and most likely never. Sure, it means no Pendolinos on the loop (someone seriously suggested that a few years ago) but most of us can live with that.

Mass conversion to AC could be achieved by reboring the 2 single bore tunnels through Moorfields to give a 4 track tunnel, 4 platforms at Central and clearances for overhead wires. If that was done there are very few, if any obstructions to OHLE between Sandhills, Southport, Preston and Wigan.

 

[Gareth]

Sounds like a lot of massively disruptive and hideously expensive work just to be rid of third rail. I also don't see the need for quadruple track between Moorfields and Central.

 

[yorksrob]

Sounds like a lot of massively disruptive and hideously expensive work just to be rid of third rail. I also don't see the need for quadruple track between Moorfields and Central.

Indeed, complete waste of money.

They need to be electrifying the diesel bits.

 

[507020]

They need to be electrifying the diesel bits.

There’s nowhere for the Diesel bits, the North Mersey Branch or the lines from Lime Street to terminate without 4 platforms at Central.

 

[Bletchleyite]

There’s nowhere for the Diesel bits, the North Mersey Branch or the lines from Lime Street to terminate without 4 platforms at Central.

Connecting other services to the southern end of the Ormskirk and Kirkby services actually creates line capacity, not removes it, by getting rid of the reversals. Nothing should operate into Central using anything other than 777s (or short-term remaining 50x).

On the other hand the island platform would get rather busy. It would be much cheaper to change it to wide side platforms as per St Pancras (at present there's a fair bit of wasted space in the station box), and so that's what I advocate now. Two islands aren't really needed as the reversing siding can be used for anything turning round instead of turning it in the platforms.

You would gain a lot of space simply by moving the accesses into newly dug bits at the side (like it is at say James St or Hamilton Square), leaving the platforms fully clear. There might not even need to be any digging out for the platform itself, or if any was needed it wouldn't need to be very much wider.

 

[507020]

Connecting other services to the southern end of the Ormskirk and Kirkby services actually creates line capacity, not removes it, by getting rid of the reversals. Nothing should operate into Central using anything other than 777s (or short-term remaining 50x).

On the other hand the island platform would get rather busy. It would be much cheaper to change it to wide side platforms as per St Pancras (at present there's a fair bit of wasted space in the station box), and so that's what I advocate now. Two islands aren't really needed as the reversing siding can be used for anything turning round instead of turning it in the platforms.

You would gain a lot of space simply by moving the accesses into newly dug bits at the side (like it is at say James St or Hamilton Square), leaving the platforms fully clear. There might not even need to be any digging out for the platform itself, or if any was needed it wouldn't need to be very much wider.

I agree with getting rid of the reversals at Ormskirk and Kirkby but if you had 2 side platforms instead of an island you’d lose any chance of a cross platform interchange so the crowding on the island platform will just move upstairs.

A good question would be that if the Edge Hill spur was built and stopping services were diverted from Lime Street to free up capacity there, would there be anything wrong with running 319s, 323s or 331s into what would now be a twin bore tunnel with AC electrification throughout and not necessitating end evacuation doors.

 

[Gareth]

There's nothing I've ever read that suggests the Edge Hill spur would involve wholesale AC electrification of the Merseyrail network. Any such insistence would merely guarantee that the work never happens.

Your posts suggest you want Merseyrail to become something radically different to what it currently is. And with respect, I don't think it's remotely realistic, nor desirable.

 

[Bletchleyite]

Your posts suggest you want Merseyrail to become something radically different to what it currently is. And with respect, I don't think it's remotely realistic, nor desirable.

I would agree. You want to consider Merseyrail extensions very similarly to Metrolink ones. They should be services which can be made mostly self-contained and run at 4tph. The electrification system is less important as there's the option of fitment of batteries or pantograph/transformer (though not both) to the 777s.

At that end of things the obvious ones are:
- Wigan NW via St Helens (with long distance services diverting via Parkside and calling at St Helens Jn and Golborne). 4tph and I'd suggest attaching to the Ormskirk as that would provide a useful through service rather than giving Kirkby two direct services to Wigan. Already 25kV so fit pantographs to enough units.
- Warrington Central (as an extension of the Hunts Cross service)

That does leave 4tph (Kirkby services) where it isn't very obvious what to do. Crewe is a bit far for Merseyrail. Chat Moss is probably better as a through Liverpool-Manchester local service which would hit Merseyrail's punctuality too much. One option would be a short extension to terminate in the barely-used slow-line platforms at South Parkway, giving a Merseyrail quality service to Mossley Hill and West Allerton.

There's not a lot else bar the reversing siding, short of an Airport extension where you might send 4 to Warrington and 4 to the Airport, or reopening Gateacre. If you did the latter you would run the services via Aigburth there, and run via the high level platforms at South Parkway to Warrington as at present. Indeed, I quite like that idea. Though you'd do it all as 25kV.

 

[507020]

There's nothing I've ever read that suggests the Edge Hill spur would involve wholesale AC electrification of the Merseyrail network. Any such insistence would merely guarantee that the work never happens.

Your posts suggest you want Merseyrail to become something radically different to what it currently is. And with respect, I don't think it's remotely realistic, nor desirable.

Merseyrail at present effectively comprises a main north - south line which makes use of a 1970s tunnel with 2 branches formed from truncated main lines as well as the isolated system on the Wirral which despite consistently lower passenger numbers enjoys a higher frequency service (not that it shouldn’t) so that is the baseline.

To start with I don’t believe I don’t believe the main line is long enough at present and could do with running from Crossens to Gateacre, if not Banks to Knotty Ash, (Since the essential and well used line to Crossens has unfortunately been built on we are left with the alternative proposal of the Burscough Curves) but even with a line of the current length, the passenger density is greater in the core section, so as on the Wirral, which had 6tph to Hooton and 8tph to Birkenhead North pre-covid, there should probably be 6tph between Hall Road to Liverpool Central, even if these are only peak extras, with 4tph running through from Southport to Hunts Cross all day. This is not fundamentally different from the current service.

I would then extend the present “branch line” services to proper termini at Preston, Wigan Wallgate and a new one at Skelmersdale, but then I would extend these proposals to include many of the lines which are able to be reopened including the Burscough Curves, North Mersey Branch, Canada Dock Branch and North Liverpool Extension. I won’t go into detail again about the many benefits to all in Southport, Ormskirk and Preston of reopening the Burscough Curves.

The problem with this however is that in combination it leaves the system top heavy with more services terminating from the north than from the south. This can be resolved by running some services through to Gateacre or beyond via the North Liverpool Extension, others to Warrington Central or Birchwood on the CLC main line and by building the Edge Hill spur and running from Central towards Anfield, St Helens, Newton-le-Willows and Runcorn or however far beyond in each direction. 777s running stopping services on the L&NWR lines wouldn’t be a bad idea but it doesn’t make sense to do so out of Lime Street. I’m fairly sure you couldn’t fit such a vast number of services or all their passengers onto a single Victorian island platform 50-100 years from now. I also thought there was some desire to free up capacity at Lime Street because of some new High Speed line or something.

If 331s could be cleared to run through a twin bore AC overhead tunnel then it would also be possible to run services to Manchester and Blackpool. The other thing no one seems to have mentioned is the need for a line from Ormskirk to Skelmersdale. I have not done anything to fundamentally change what are still the Merseyrail type services, I have just extended them comprehensively to more of the surrounding places. I wouldn’t actually wire through to Central from the north straight away, I would merely provide clearances for it to be converted eventually because the 3rd rail won’t last forever, but an Edge Hill spur would have to be AC from day 1 at least as far as Central from the south if you were going to have AC trains running through to AC destinations.