Quadruple Line Track Layouts

[MK Tom]

This is something that has interested me for a long time. On my travels I've observed four ways of arranging four-track lines in the UK. They are:

US DS UF DF (e.g. WCML south of Hanslope, MML south of Bedford)

US UF DF DS (e.g. most of ECML, WCML in Trent Valley)

UF US DS DF (Metropolitan south of Harrow-on-the-Hill)

US UF DS DF (WCML Rugby-Nuneaton)

Can anyone tell me why there are these different systems? Is any one better for any reason than the others? What determining factors would influence a choice between them? And what's the most common, both nationally and worldwide? Thanks!

 

[Wyvern]

On the Midland Main Line the Up and Down Goods are to one side of the Up and Down Fast so they pass behind the stations e.g: Chesterfield, Derby, Loughborough, Syston (as it used to be I think) etc etc.

Elsewhere, like north of Belper, the goods lines are on either side of the fasts since they are easier to divert into.

On some lines such as on the WCML the fast lines run through the centre of a station, away from the platforms, while the slow lines at either side allow for stopping trains, as at Tamworth Low Level etc. Sometimes the slow lines are no more than loops in this case.

Much of the variation I imagine originated with the individual practices of the nineteenth century railway companies.

 

[swt_passenger]

This is something that has interested me for a long time. On my travels I've observed four ways of arranging four-track lines in the UK. They are:

US DS UF DF (e.g. WCML south of Hanslope, MML south of Bedford)

US UF DF DS (e.g. most of ECML, WCML in Trent Valley)

Those ^^^ are the two main variants, the others are minor variations. The WCML south situation you describe is known as paired by use, the ECML style is known as paired by direction.

Paired by use is believed the best method of laying out the tracks for a terminus station on a four track route, as it reduces crossing moves at the terminus, and allows for groups of services to use adjacent platforms, a good example of this is the main line side at Waterloo. I forget the exact dates, but this layout originally extended out at least as far as the branch to Kingston, where both the slow lines ran under the main lines. (The second unused underpass there is still visible.)

Paired by use is fine in the absence of branches - or where most branches are on the same side of the formation - an example of this might be the GWML out towards Reading.

When the SWML was four tracked out towards Woking and Basingstoke, the decision was made to change from paired by use to 'paired by direction'. Having decided that most branch junctions would be grade separated, and a flyover was built just east of Wimbledon to switch the up slow over the fast lines - because when adding the many grade separated junctions (which are on either side of the main route), it was realised the civil engineering was no more difficult, but the advantage was that with suitable crossover locations fast and slow trains could both easily access the branch lines. This is much more practical than having the conflicts that ensue when a slow train has to access a branch on the 'wrong side' of the fast lines, IYSWIM.

Pairing by direction also means that it is easier to have timetabled overtaking, easier to recover from a failed train, and easier to have services that run fast initially but change to a stopping pattern further away from the terminus.

 

[Wyvern]

On the Midland Main Line the Up and Down Goods are to one side of the Up and Down Fast so they pass behind the stations e.g: Chesterfield, Derby, Loughborough, Syston (as it used to be I think) etc etc. .

Afterthought: At these stations the goods lines were kept separate from the platforms of course, (as with Derby Nottingham Road) but also they were put in many years after the original two-track line was laid, so could not easily run in front of the stations as they would have to if they were to be laid either side of the fast lines.

 

[yorksrob]

Those ^^^ are the two main variants, the others are minor variations. The WCML south situation you describe is known as paired by use, the ECML style is known as paired by direction.

Paired by use is believed the best method of laying out the tracks for a terminus station on a four track route, as it reduces crossing moves at the terminus, and allows for groups of services to use adjacent platforms, a good example of this is the main line side at Waterloo. I forget the exact dates, but this layout originally extended out at least as far as the branch to Kingston, where both the slow lines ran under the main lines. (The second unused underpass there is still visible.)

Paired by use is fine in the absence of branches - or where most branches are on the same side of the formation - an example of this might be the GWML out towards Reading.

When the SWML was four tracked out towards Woking and Basingstoke, the decision was made to change from paired by use to 'paired by direction'. Having decided that most branch junctions would be grade separated, and a flyover was built just east of Wimbledon to switch the up slow over the fast lines - because when adding the many grade separated junctions (which are on either side of the main route), it was realised the civil engineering was no more difficult, but the advantage was that with suitable crossover locations fast and slow trains could both easily access the branch lines. This is much more practical than having the conflicts that ensue when a slow train has to access a branch on the 'wrong side' of the fast lines, IYSWIM.

Pairing by direction also means that it is easier to have timetabled overtaking, easier to recover from a failed train, and easier to have services that run fast initially but change to a stopping pattern further away from the terminus.

Interestingly the opposite happenned on the Chatham line through Bromley South at around the time of electrification. These were originally paired by direction and later switched to paired by use, presumably because of the lack of grade seperated junctions.

 

[SwindonPkwy]

swt_passenger, great explanation. I feel a job at Network Rail beckons!

So, what happens when opposing configurations meet, such as on WCML?

 

[swt_passenger]

swt_passenger, great explanation. I feel a job at Network Rail beckons!

So, what happens when opposing configurations meet, such as on WCML?

Ah - I've looked at that before!

The two configurations (ie south of Rugby and through the Trent Valley) don't actually meet, because there's a convenient section of three tracking, and that section, in combination with the south end flyovers near Rugby station allows the tangle of lines to get sorted out.

However, if they ever intended to have a complete four track railway between Rugby and Nuneaton in the down direction, they end up with a problem because the down slow would have to get from the middle of the formation in Rugby station to the outside by Nuneaton. My theory is that the three track section will remain as the cheap and nasty solution - otherwise they'll need a new flyover somewhere...

 

[Ploughman]

Typical example of a change point is Skelton Bridge and junction just North of York.
Where the Up Slow moves across.

 

[jopsuk]

swt_passenger, great explanation. I feel a job at Network Rail beckons!

So, what happens when opposing configurations meet, such as on WCML?

You could always have a flyover or flyunder, like at the approaches to Kings Cross where the Up Slow crosses the Fast lines to access the Suburban shed.

In fact, surely this is the ideal, if you can afford to build the infrastucture where it is needed- have "paired by direction" for most of the route and "paired by use" at the terminus?

Also, do remember that on the Great Western it is "Main" and "Relief" lines, and that references there to "Fast" and Slow" tend to get met with anger; possible death.

 

[MK Tom]

Ah - I've looked at that before!

The two configurations (ie south of Rugby and through the Trent Valley) don't actually meet, because there's a convenient section of three tracking, and that section, in combination with the south end flyovers near Rugby station allows the tangle of lines to get sorted out.

However, if they ever intended to have a complete four track railway between Rugby and Nuneaton in the down direction, they end up with a problem because the down slow would have to get from the middle of the formation in Rugby station to the outside by Nuneaton. My theory is that the three track section will remain as the cheap and nasty solution - otherwise they'll need a new flyover somewhere...

There is a flyover - the paired by direction actually starts just south of Rugby where the Northampton loop comes in. Then you have the bit north of Rugby before it drops to three where it's paired by direction but for some reason the down fast and slow are the wrong way round. I don't think it'd take too much effort to switch them in the event of four-tracking the rest of that stretch.

Thanks to everyone especially the third post for the fantastic explanations.

Any ideas about the Met where the fasts are on the outside?

 

[swt_passenger]

There is a flyover - the paired by direction actually starts just south of Rugby where the Northampton loop comes in. Then you have the bit north of Rugby before it drops to three where it's paired by direction but for some reason the down fast and slow are the wrong way round.

That's why I mentioned the south end flyovers above.

The key issue is that the branching to Coventry has to be dealt with, so through the station itself you effectively have a down slow Coventry in P1, a down fast which divides, and a duplicate down slow towards Nuneaton through P2. It is that third down track which causes the difficulty, but if you didn't have it slow trains from Northampton would only be able to get to the Trent Valley route north of the station, where they'd conflict with trains off the down fast heading to Coventry.

Any ideas about the Met where the fasts are on the outside?

If this can't explain why, I don't think anything will...

http://www.davros.org/rail/culg/metropolitan.html

 

[John Webb]

When the Midland Railway built the London Extension from Bedford to St Pancras, they could not afford to build all the four lines at once, although they did buy sufficient land at the outset for this to be done. A goods line was laid in for part of the distance. In the early 1890s the goods lines were developed to give four lines - the Down and Up passenger lines and the down and up goods. (The present St Albans South signal box dates from 1892 when this happened.) In 1906 the goods lines were converted to passenger lines with the development of commuter traffic and appropriately resignalled, to give the current US DS UF DF which is still with us today.

 

[adc82140]

From an engineering point of view, is paired by use any better? I've noticed that the SWML is plagued by weekend bustitutions during engineering as much work requires a complete line block, wheras by and large the GWML goes down to two line operation during engineering (except for the major stuff) and trains continue running (except if you're unfortunate enough to need Burnham, Taplow or Pangbourne stations )

 

[Trog]

I believe the Midland actually had enough land to allow six tracks, (south of Luton?). The laying of the fifth and sixth tracks from Luton to Hendon being aborted by the First World War.

 

[martinsh]

So, what happens when opposing configurations meet, such as on WCML?

You plonk a station at the changeover point and call it Crewe !

 

[jopsuk]

From an engineering point of view, is paired by use any better? I've noticed that the SWML is plagued by weekend bustitutions during engineering as much work requires a complete line block, wheras by and large the GWML goes down to two line operation during engineering (except for the major stuff) and trains continue running (except if you're unfortunate enough to need Burnham, Taplow or Pangbourne stations )

It can be that way, certainly- or you can really splash out, build the whole thing as fully bidirectional at full line speed on all four tracks and operate paired by direction under normal use and paired by use for engineering blockades...

As for the Met?

Was it originally built as a twin track with island platforms, so when they wanted to add fast lines without platforms but paired-by-direction, putting the Fast lines outside the Slow was the way to do it?

 

[Wyvern]

The Midland north of Leicester was originally twin track in 1840. The goods lines were added at the end of the century. Hence they had to run behind stations generally speaking though one station that was rebuilt was Duffield.

The original Trent Valley Line, certainly as far as Tamworth Low Level was concerned, was built as twin track with platform loops at intermediate stations.

 

[MK Tom]

It strikes me that paired by direction massively reduces flexibility - as someone else said about the GWML, most Sunday mornings the WCML through here is reduced to two tracks to facilitate engineering work. You can't do that with paired by direction because the fast lines don't have platform faces at Tamworth/Rugeley/Sandy/Huntington etc etc. I always thought this was the reason that Cheddington and Apsley and stations like them have fast line platforms?

 

[John Webb]

I believe the Midland actually had enough land to allow six tracks, (south of Luton?). The laying of the fifth and sixth tracks from Luton to Hendon being aborted by the First World War.

There certainly was not enough room for six tracks at St Albans - they only had enough room for four plus the engine-shed access by nicking a bit of the then-new St Albans City jail! (But that's another story!)

As far as I am aware they only got enough land for 6 tracks from Silkstream Junction, just north of Hendon, where the goods went to/from their own lines from/to the slow lines via a fly-over arrangement to avoid a level crossing of the fast lines. (This dates from the 1890s expansion of the goods lines.)

 

[Aictos]

What about the Great Eastern Main Line which is paired by use so far, thing is they call their lines Electrics and Mains compared to Mains/Reliefs or Fasts/Slows.

 

[swt_passenger]

It strikes me that paired by direction massively reduces flexibility - as someone else said about the GWML, most Sunday mornings the WCML through here is reduced to two tracks to facilitate engineering work. You can't do that with paired by direction because the fast lines don't have platform faces at Tamworth/Rugeley/Sandy/Huntington etc etc. I always thought this was the reason that Cheddington and Apsley and stations like them have fast line platforms?

On the SWML many of the central platforms that would have allowed for degraded working during engineering works (where bi-directional signalling is also available) were either removed many years ago, or are not in normal use - which effectively means they might as well be ignored for all the use they get.

There are usually going to be trade offs between the long term normal usage and temporary capability for relatively few hours at a time during engineering works, and presumably the day to day operations usually win.

 

[Bald Rick]

The ideal is paired by use, with a nice big gap between the two pairs, and the middle two lines bi-di. Offers best day to day flexibility and the ability to take a pair out for decent engineering work. This is exactly what the Trent Valley is from Nuneaton to Colwich.

 

[Pumbaa]

The ideal is paired by use, with a nice big gap between the two pairs, and the middle two lines bi-di. Offers best day to day flexibility and the ability to take a pair out for decent engineering work. This is exactly what the Trent Valley is from Nuneaton to Colwich.

Err, fairly sure that stretch is paired by direction (DS DF UF US). Once you get past Stafford (we're ignoring the Colwich area here) it becomes paired by use (slows on the southern side for Basford Hall etc).

 

[Bald Rick]

Err, fairly sure that stretch is paired by direction (DS DF UF US). Once you get past Stafford (we're ignoring the Colwich area here) it becomes paired by use (slows on the southern side for Basford Hall etc).

You're quite right, and paired by direction is what I meant! Honest guv. Been a long day.

 

[Pumbaa]

I know the feeling.

I personally feel that paired by direction is the best option, with platforms on all tracks where possible.

 

[Trog]

There certainly was not enough room for six tracks at St Albans - they only had enough room for four plus the engine-shed access by nicking a bit of the then-new St Albans City jail! (But that's another story!)

As far as I am aware they only got enough land for 6 tracks from Silkstream Junction, just north of Hendon, where the goods went to/from their own lines from/to the slow lines via a fly-over arrangement to avoid a level crossing of the fast lines. (This dates from the 1890s expansion of the goods lines.)

I am sure I saw land plans in the 1980's that showed the railway owning a strip of land wide enough for another two tracks on the slow line side, although most of it was included in farmers fields. There are also some strips of land along side the track, by the M1 service station and north of Radlett station that may be a relic of this project.

 

[jopsuk]

What about the Great Eastern Main Line which is paired by use so far, thing is they call their lines Electrics and Mains compared to Mains/Reliefs or Fasts/Slows.

That's a hangover from the days when it was electrified to Shenfield- only the local "metro" lines were wired up whilst the Mainline to Norwich etc wasn't (as I understand it). Therefore, at the time, "Main" and "electric" made some sort of sense.

 

[Old Timer]

I am sure I saw land plans in the 1980's that showed the railway owning a strip of land wide enough for another two tracks on the slow line side, although most of it was included in farmers fields. There are also some strips of land along side the track, by the M1 service station and north of Radlett station that may be a relic of this project.

Both were the locations of sidings many, many years ago.

There was a signalbox called Scratchwood Sidings at that location. The sididngs served a former quarry into which the locomotive ash from Cricklewood depot was disposed by train. I imagine it would also have received ash from St Albans as well. The box closed about 1962 or soon after.

This was also the location where part of the film "Passport to Courage" starring Dirk Bogard was made, and on April 2nd 1962, Fowler 4MT 42325 and a train of 25 wagons were drien through the sidings and into the tip to form a spectacular train crash scene. The locomotive and wagons were never recovered and were subsequently entombed under the Scratchwood services car park.

At Napsbury, there was a siding on the Up side which served the Middlesex County Asylum. I believe there may also have been a connection into the former Handley Page aircraft factory because of the way the cutting has been cut away on the Down Side.

Napsbury was the only Midland (London Extension) station which consisted soley of an Island platform on the slow lines. That is why the signalbox was situated in between the Slow lines rather than to one side of the line. I deliberately exclude Kentish Town from that.

 

[Oswyntail]

....
This was also the location where part of the film "Passport to Courage" starring Dirk Bogard was made, and on April 2nd 1962, Fowler 4MT 42325 and a train of 25 wagons were drien through the sidings and into the tip to form a spectacular train crash scene. The locomotive and wagons were never recovered and were subsequently entombed under the Scratchwood services car park. .....

Slightly wandering from topic..
The film - actually "The Password is Courage" - also includes scenes at Victoria Station (London) where POWs are put on trains, and Radlett, where they detrain. Of course, as the action is in Poland, i could be mistaken and they are using genuine Polish stations that just look like British ones
Back to the fascinating proper topic.

 

[Wyvern]

Napsbury was the only Midland (London Extension) station which consisted soley of an Island platform on the slow lines.

WAsnt the reason for that because its purpose was to serve the hospital?