3rd rail systems outside of the uk?

stuu

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The city state Singapore is a perfect example of somewhere DC would be perfectly adequate, but does this mean the trains on a Bangkok - Kuala Lumpur - Singapore high speed line would have to switch to 3rd rail as soon as they cross the Johor Strait?
No, the plan was for it to be in a tunnel; one or possibly more of the metro lines does use overhead but it's entirely underground
 
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DanielB

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Arguably it's easier to combine 3rd rail with level crossings than OHLE is, because OHLE needs its level raised to allow tall vehicles to pass underneath. Take a look at Foxton (Cambs) where the railway crosses the A10 as an example - if you look at this video, you'll see the pantographs are at full stretch.
Those pantographs at full stretch probably have more to do with the small UK loading gauge in relation to the height of the OHLE. As seen here that's much less an issue on the continent.
 

edwin_m

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If 3rd rail is so unsatisfactory, why do most Metros, including new ones, use it?

Such comparison discussions never seem to feature any sensible cost anaylsis of the two approaches. At installation, the 3rd rail goes down notably quickly, without the extended time, cost, and heavy civils work that overhead does. I actually watched in the mid-1980s the laying of 3rd rail on the Stratford to North Woolwich line. It virtually seemed to go in over one weekend - works train propelled by an 08 shunter, rails offloaded directly to location, bolted down, team ahead screwing in insulators, move forward one rail length to the next one. No civils, no bridge lifting, done. Cost maybe 5% per mile of what it took on the Goblin with overhead.

All the stuff about more lineside substations, but on a conventional 12-car 25kV emu there are 3 substations, transformer and everything, under each train, one per motor coach. This one is sometimes rebutted by stating that things have got more efficient with power electronics. Well, so have lineside structures benefited equally.

We may contrast two similar "intermediate" systems in Britain, developed at broadly similar times, the Tyne & Wear and the DLR. One went for overhead, the other for 3rd rail. Which in retrospect was the better solution?
Power electronics have made regenerative braking pretty much universal on new trains whether AC or DC, which nullifies some of the weight penalty of carrying the transformer.
Metros tend to use it because they usually include tunnelled sections and costs increase exponentially if you attempt to increase the tunnel diameter to accommodate overhead wires. A new overhead AC powered railway has just opened in a tunnel and how late was it?
Lower voltages (which generally means DC) are better for systems with short distances, frequent stops and intensive service. The trains/trams don't need a transformer, which saves space and weight and therefore energy, and the losses due to resistance in the rails or wires are less over shorter distances. The reverse applies with higher voltages being better for longer-distance services.

Since 25kV first became viable in the 1950s, there can't be many main line railways that have started a new electrification (excluding metros and extensions to existing networks) on any other system. The only ones I can think of offhand are a couple of heavy haul railways that went for 50kV. And several countries which already had extensive mileage at other voltages have chosen 25kV for new projects.
 

etr221

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One example I can think of not mentioned so far is Buenos Aires (Argentina), but I don't know details - I think several of the railways radiating from the city had suburban electrification schemes which are still going - and have relatively recently acquired new trains.

The New York systems mentioned - Long Island (formerly owned by the PRR) and Metro-North (former New York Central) extend a fair way out of the city, and the LI is quite an extensive network - probably second to the Southern. The original Pennsylvania electrification west from New York through the tunnels under the Hudson was third rail (same as the LIRR), I think as far as Newark - converted to overhead ac in the 1930s.

Other main line 3rd rail systems I can think of that have gone are Cleveland Union Terminal - didn't go far out, replaced by through working of diesels; while the Italians had a couple of third 3rd rail schemes: a very early one (from 1901-1902) from Milano to Varese and Porto Ceresio; and somewhat out from Napoli Centrale - the line west through tunnels from the station, plus a bit more, from Gianturco to Villa Literno. Both these were converted to the Italian standard 3kv dc overhead in due course.
 

HSTEd

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It's worth nothing that at the time of the fall of the Soviet Union they were doing serious development work on 6kV or 12kV DC systems, which capture the benefits of the high voltages seen in typical modern AC systems but also allowed (in an era before massive static frequency converters!) train systems to operate practically in very weak AC grids like those found in the rural interior of the Soviet Union. Which was one of the reasons 3kV electrification continued right up until the fall of the Soviet Union.
 

Romsey

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Indeed, were the original Southern Region suburban routes not just a glorified metro system ? At least until the Brighton and Portsmouth lines were electrified, and the system subsequently extended, eg to the Kent Coast and Bournemouth, then Weymouth, by BR. There must come a point where a 3rd rail system has become so extensive that converting it to OLE becomes impossible, because the benefits are outweighed by the cost and disruption during changeover. Having said that, IMHO it is a pity that the Bournemouth line did not receive 25kV OLE instead of 3rd rail, from Woking outwards, but no doubt there were good reasons.
There were two major reasons - cost and simplicity of rolling stock.
No doubt dial voltage stock could have been developed in the 1960's but it would have been heavy, expensive and inefficient.
 

MarcVD

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Yes, but a large proportion of the 25kV AC network is comprised by new build high speed lines, the LGV Sud-Est was the first AC line in France. Before 1981, the SNCF was entirely DC and conventional lines remain mostly DC, but I believe there have been a few conversions.
Uh ? Look at the attached map. Green is 1,5 kV=, red (high speed) and orange are 25 kV ~ 50 Hz.French_railway_network.svg.png

It's worth nothing that at the time of the fall of the Soviet Union they were doing serious development work on 6kV or 12kV DC systems, which capture the benefits of the high voltages seen in typical modern AC systems but also allowed (in an era before massive static frequency converters!) train systems to operate practically in very weak AC grids like those found in the rural interior of the Soviet Union. Which was one of the reasons 3kV electrification continued right up until the fall of the Soviet Union.
You mean weak in the sense that they would not sustain an unbalanced load like the one created by an AC substation ? Not sure of that. There are substantial parts of the transsiberian railway, and also of the BAM, that run in the middle of nowhere, and have 25 kV 50 Hz electrification since the 70ies. The advantage being that the substations can be located much farther apart.
 
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HSTEd

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You mean weak in the sense that they would not sustain an unbalanced load like the one created by an AC substation ? Not sure of that. There are substantial parts of the transsiberian railway, and also of the BAM, that run in the middle of nowhere, and have 25 kV 50 Hz electrification since the 70ies. The advantage being that the substations can be located much farther apart.

And substantial resources were expended to strengthen the grids to enable that to happen.
 

Gag Halfrunt

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One example I can think of not mentioned so far is Buenos Aires (Argentina), but I don't know details - I think several of the railways radiating from the city had suburban electrification schemes which are still going - and have relatively recently acquired new trains.

The Urquiza Line is standard gauge and has 600 V DC third rail.

The Mitre Line and Sarmiento Line are 1676 mm gauge and have 800 V DC third rail.

The Roca Line is 1676 mm gauge and has 25 kV OHLE. Other lines around Buenos Aires are not electrified.
 

TRAX

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I don’t know if there’s much now. Most electrified conventional lines in France use a 1500V DC overhead system. An AC system was being considered, but the French army insisted on DC so it could quickly relay the 3rd rail in the event of world war 3. It has never been done and all existing 3rd rail was ripped up and converted to overhead years ago. We just never spent the money doing it, which is the legacy of the Southern, as well as the L&Y, Mersey and Wirral Railways don’t forget.
Most? There’s a large proportion of French railways electrified at 25kV AC.

Surely, virtually all 3rd rail on French mainlines has been removed now. For 1500VDC vs 25Kv ac, I would say that although actual 1500VDC track miles might exceed that on ac, the volume of traffic is far higher under ac OLE.

Uh ? Look at the attached map. Green is 1,5 kV=, red (high speed) and orange are 25 kV ~ 50 Hz.View attachment 115822


You mean weak in the sense that they would not sustain an unbalanced load like the one created by an AC substation ? Not sure of that. There are substantial parts of the transsiberian railway, and also of the BAM, that run in the middle of nowhere, and have 25 kV 50 Hz electrification since the 70ies. The advantage being that the substations can be located much farther apart.

52 % of the French railway network is electrified.

37 % of the electrified French railway network is 1.5 kV DC. 63 % is 25 kV AC (19 % of that 25 kV AC network being high-speed lines).

So the vast majority is 25 kV AC, with less than a quarter of this being high-speed lines.
 

AM9

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Yes you are right, I was sure that it was 4ft when I travelled on it in 2001.
 

plugwash

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Arguably it's easier to combine 3rd rail with level crossings than OHLE is, because OHLE needs its level raised to allow tall vehicles to pass underneath. Take a look at Foxton (Cambs) where the railway crosses the A10 as an example - if you look at this video, you'll see the pantographs are at full stretch.
Which isn't really a problem unless there is also a low overbridge in the area.



Whereas 3rd rail is just terminated a few feet short of the crossing.
Not a problem for a 3+ car multiple unit, but there is the risk of a locomotive or small multiple unit getting "gapped" if for any reason they stop on the crossing. AIUI fdue to the risk of gapping 2 car EMUs used in recent times were always operated as part of a longer train.
 

A0wen

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Which isn't really a problem unless there is also a low overbridge in the area.




Not a problem for a 3+ car multiple unit, but there is the risk of a locomotive or small multiple unit getting "gapped" if for any reason they stop on the crossing. AIUI fdue to the risk of gapping 2 car EMUs used in recent times were always operated as part of a longer train.

Aren't OHLE level crossings also 'neutral' zones to prevent the risk of arcing with tall vehicles (so the wire is there for continuity to guide the pantograph) ? So there's a risk an OHL loco or EMU can get caught in the neutral zone and most of those only have 1 pantograph in or near the centre, whereas a 3rd rail EMU will usually have pick up shoes at each end.
 

Falcon1200

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There were two major reasons - cost and simplicity of rolling stock.

Good point, given that some of the 'new' stock for the Bournemouth electrification was actually second-hand Mark 1 coaches, clearly BR did have to do it on the cheap !

Aren't OHLE level crossings also 'neutral' zones to prevent the risk of arcing with tall vehicles (so the wire is there for continuity to guide the pantograph) ?

Not as far as I know, no; Certainly none of the LCs on OLE routes in Scotland are 'neutral zones', the OLE is live throughout.
 

stuu

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Aren't OHLE level crossings also 'neutral' zones to prevent the risk of arcing with tall vehicles (so the wire is there for continuity to guide the pantograph) ? So there's a risk an OHL loco or EMU can get caught in the neutral zone and most of those only have 1 pantograph in or near the centre, whereas a 3rd rail EMU will usually have pick up shoes at each end.
No, not normally. I expect you can find videos on YouTube of what happens when an overheight vehicle hits the wires
 

AM9

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No, not normally. I expect you can find videos on YouTube of what happens when an overheight vehicle hits the wires
The only cases where I've heard that is where a tramline crosses an OLE electrified railway, in which case there's a fuctional necessity to interrupt the power.
 
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dutchflyer

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Is not there 1 other line not mentioned? The ´little yellow metro in the Pyrenees´ by SNCF, along spanish border, east from La Tour de Carol till (I think, from memory) Villefranche. Started with handmedown ex RATP/Paris metro stock. Though I vaguely also recall it may have been rebuilt to more normal standard. In a very, very rural area.
Tipical this system of 3d rail was after being built for very heavy lines in areas larger as metro-and very soon overtaken by newer developments. Then if the old system was too large to rebuild it, it kept that way. Which probably explains the quaint british networks.
(law of braking progress-is the literal translation of how this is called here-but I guess thats no british saying).
How many of these systems (not just short single end of lines) were rebuilt to the overwhelming standard of overhead lines?
 

stuu

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Is not there 1 other line not mentioned? The ´little yellow metro in the Pyrenees´ by SNCF, along spanish border, east from La Tour de Carol till (I think, from memory) Villefranche. Started with handmedown ex RATP/Paris metro stock. Though I vaguely also recall it may have been rebuilt to more normal standard. In a very, very rural area.
Tipical this system of 3d rail was after being built for very heavy lines in areas larger as metro-and very soon overtaken by newer developments. Then if the old system was too large to rebuild it, it kept that way. Which probably explains the quaint british networks.
(law of braking progress-is the literal translation of how this is called here-but I guess thats no british saying).
How many of these systems (not just short single end of lines) were rebuilt to the overwhelming standard of overhead lines?
Mentioned in post 6 and 26. I don't think any of the stock comes from Paris. Maybe somewhere else does though?
 

67thave

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An odd example is the Staten Island Railway in New York City. While commonly classified as an urban rail network and often associated with the city's subway system, the third-rail electrification of the network dates back to when the service was a mainline railway operated as part of the Baltimore & Ohio.
 

delt1c

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Part of the Sofia metro is bottom contact 3rd rail
 

SHD

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Mentioned in post 6 and 26. I don't think any of the stock comes from Paris. Maybe somewhere else does though?

Maybe Dutch flyer’s confusion comes from the fact that the original rolling stock of the petit train jaune had (pre-modernization) a passing resemblance to early Paris metro trains?

1654608182674.jpeg

1654608440362.jpeg
(Original Paris metro rolling stock on the left)
 
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MarkyT

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Another reason why big city urban metros can continue to use ground level conductor rail more easily than other railways, even on new lines, is that typically the infrastructure is completely segregated with no level crossings, excellent fencing, or inaccessibility to incursions conferred by other means such as tunnels and viaducts etc. Traffic usually has to stop completely for any on-track maintenance activity anyway on such busy systems, so enforced power isolations for staff safety are also not onerous.
 

JWK

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I think I’m correct that Amtrak continue to operate some dual-mode long distance locomotives with limited third rail capability alongside their diesel engines for use in the underground stations at Penn and Grand Central due to the ban on diesel engines in the confined spaces?

Interestingly ‘a third rail issue’ is a common phrase in US politics (‘you touch it and you die’), but I guess that has more to do with east coast familiarity with subway systems than mainline applications!
 

JonasB

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Arguably it's easier to combine 3rd rail with level crossings than OHLE is, because OHLE needs its level raised to allow tall vehicles to pass underneath. Take a look at Foxton (Cambs) where the railway crosses the A10 as an example - if you look at this video, you'll see the pantographs are at full stretch.

Whereas 3rd rail is just terminated a few feet short of the crossing.

That is an issue that is probably unique to the UK since the normal height of the wire is pretty low, but there is nothing that prevents you from mounting it higher. Such as the rest of Europe where is it usually a metre higher, and in North America it is even higher. And, is there really a problem? The pantographs are designed to adapt to the height of the wire and are doing just that in the video.

3rd rail on the other hand will have large gaps at level crossings, which is not that great for loco hauled trains.
 

S&CLER

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Is not there 1 other line not mentioned? The ´little yellow metro in the Pyrenees´ by SNCF, along spanish border, east from La Tour de Carol till (I think, from memory) Villefranche. Started with handmedown ex RATP/Paris metro stock. Though I vaguely also recall it may have been rebuilt to more normal standard. In a very, very rural area.
Tipical this system of 3d rail was after being built for very heavy lines in areas larger as metro-and very soon overtaken by newer developments. Then if the old system was too large to rebuild it, it kept that way. Which probably explains the quaint british networks.
(law of braking progress-is the literal translation of how this is called here-but I guess thats no british saying).
How many of these systems (not just short single end of lines) were rebuilt to the overwhelming standard of overhead lines?
I came across this "wet van de remmende voorsprong", as I think it was, once and had to rack my brains to think of an idiomatic translation - the law of the retarding lead was one idea, or the penalty of precocity.

Back on topic, I don't think anyone has mentioned the Californian interurban the Sacramento Northern, which had 3rd rail and trolley wire sections, derived from its origin as a merger of 2 earlier lines with different systems. The 3rd rail was in open country north of Sacramento and was completely unprotected, not even fenced.
 

ac6000cw

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I think I’m correct that Amtrak continue to operate some dual-mode long distance locomotives with limited third rail capability alongside their diesel engines for use in the underground stations at Penn and Grand Central due to the ban on diesel engines in the confined spaces
You are correct, 18 x GE P32AC-DM, with Metro North running another 31 of them, and LIRR running 20 EMD DM30AC 'dual-mode' locos.
 

nlogax

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My long time favourite is the PATCO Hi-Speed Line from suburban SJ into Philadelphia. 14 miles end to end, 750V top-contact system which only properly becomes a subway once it disappears under Center City after it descends the Ben Franklin bridge. For the bulk of the journey it's an above ground limited stop railway a bit like the outer stretches of the Metropolitan line from Harrow to Moor Park.
 

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