Common passing loop for Up and Down lines

[MickeyMoggs]

Working in a limited space (aren't we all) and was wondering if anyone was aware of a prototype where where an Up line and and Down line shared a passing loop, or would it have been completely forbidden in steam practice (esp. GWR)? ie, two lines in, three lines for a distance than back down to two, with both lines being able to access the central "loop". Many thanks in advance.

[Wickham Green too]

There's no reason it would have been forbidden if the appropriate signal protection was in place - but bear in mind that what is likely to need passing is likely to be a lumbering freight train - which is likely to be a lumbering coal train - heading away from the coalfields and you'll find that a loop on one side ( generally Up, away from South Wales in the case of the G.W.R. ) would be more common. This would permit the fast lines to remain straight and - with the appropriate signal protection - could be made available for Down services if necessary.

[Phil Bullock]

Theres such a loop between the slow lines leaving Reading in the up direction. Havent sussed out if it is currently bi-directional will check tomorrow 

[corneliuslundie]

An interesting question as it seems to have ben a common arrangement in the USA. But I can't think of a British example.

Jonathan

[St. Simon]

14 minutes ago, Phil Bullock said:

Theres such a loop between the slow lines leaving Reading in the up direction. Havent sussed out if it is currently bi-directional will check tomorrow 

 

Hi Phil,

 

Yep, there is a loop between the Up and Down Reliefs, although it is described as Kennet Loop on the signalling plan, but Kennet Passenger Loop on the Sectional Appendix, and I'm sure I've seen it described as Kennet Down Goods Loop somewhere, not sure where!

 

The Loop is sort of Bi-directional, both Up and Down Direction trains can enter it, but only Down Direction trains can leave it. . Up Direction Trains can enter the loop from any of the four lines on the country side, but are stopped by a squat fixed red at the London end of the loop. It is primarily used for storing trains turning back at Reading to save Platform Space (although generally not very often and even then only for a few minutes), freight can be looped in there, but I think the preference is to hold freights on the country side of Reading, as there's more space.

 

Simon

[beast66606]

Tebay has an up / down loop - although not central. This was introduced when Carlisle PSB too control of the area in the early 1970s

 

Small part of RailCam diagram.

Edited February 22, 2021 by beast66606

[Mike_Walker]

24 minutes ago, St. Simon said:

 

Hi Phil,

 

Yep, there is a loop between the Up and Down Reliefs, although it is described as Kennet Loop on the signalling plan, but Kennet Passenger Loop on the Sectional Appendix, and I'm sure I've seen it described as Kennet Down Goods Loop somewhere, not sure where!

 

The Loop is sort of Bi-directional, both Up and Down Direction trains can enter it, but only Down Direction trains can leave it. . Up Direction Trains can enter the loop from any of the four lines on the country side, but are stopped by a squat fixed red at the London end of the loop. It is primarily used for storing trains turning back at Reading to save Platform Space (although generally not very often and even then only for a few minutes), freight can be looped in there, but I think the preference is to hold freights on the country side of Reading, as there's more space.

 

Simon

Kennet loop was upgraded from Goods to Passenger standards as part of the Reading project.

[Nearholmer]

Milton Keynes Central is a study in the practice nowadays, which occasionally causes confusion to customers as trains can be routed to "abnormal" platforms. It is often used to allow intercity passenger trains to overtake one another on the fast roads, and can be used to hold a freight train on the Up slow roads, although that is rare, because it is better to recess a train slightly further south, where it doesn't hog a platform.

 

I'm struggling to think of a "steam days" example, although there was three-track section into one of the Southern London Termini (Holborn Viaduct??) which was signaled in the 1920/30s so that the centre road could be used in either direction. I don't think it was bi-directional in the modern sense though, I think it was switched to become Up in the morning peak and Down in the evening, and that some ceremony was involved in changing its direction.

 

 

[Pete the Elaner]

I can think of some modern examples.

Tring was remodelled about 15 years ago with a line between the up & down slow. This is used mainly for terminating services but could also be used as a passing loop.

Milton Keynes Central was given the same treatment immediately afterwards to both fast & slow lines. The slow line loop is used mainly for turning services around but I have seen the fast line loop used to increase service frequency when trains would otherwise be queuing to stop because of delays & also for terminating failed trains. I am not sure if any services are rostered for it.

[SR71]

8 minutes ago, Nearholmer said:

I'm struggling to think of a "steam days" example, although there was three-track section into one of the Southern London Termini (Holborn Viaduct??) which was signaled in the 1920/30s so that the centre road could be used in either direction. I don't think it was bi-directional in the modern sense though, I think it was switched to become Up in the morning peak and Down in the evening, and that some ceremony was involved in changing its direction.

 

 

I recall reading of a similar arrangement in a loco man's memoir years ago but couldn't tell you where.

[ikcdab]

The relief line West of Taunton is the "up / down relief". It's not between the main lines, but it is a bidirectional loop.

[H2O]

I used to think that the central lines between the platform lines at Bath and Chelmsford were 'avoiding' lines to hold a slower train or let faster non-stop services pass stopping ones. However in the signal box diagrams I have seen in both cases they were connected as long trailing crossovers. Were they alway like that or were they ever used as loops?

[MickeyMoggs]

Chaps, many thanks for the responses, I think the real answer lies in the signalling, but that'll ding dang do for me. Many thanks for your help.

[The Pilotman]

It doesn’t help the OP at all but there is an example of exactly what he describes not far from where I live. It’s a few km north-east of Osnabrück on the main line to Bremen and Hamburg. The “six-foot” gradually widens to accommodate a central bi-directional loop accessible from both lines in both directions. It can also be used as a crossover in both directions (as long as the loop isn’t occupied of course) as the running lines are bi-directional. The first time I saw it I wondered why, given its flexibility, I’d never seen the arrangement in the UK. 

Edited February 23, 2021 by Western Aviator

[Phil Bullock]

Thanks to @St. Simon and @Mike_Walker for follow-up of my comments. Could not see it this morning as photo bombed by a stone train ....

[caradoc]

14 hours ago, St. Simon said:

Yep, there is a loop between the Up and Down Reliefs, although it is described as Kennet Loop on the signalling plan, but Kennet Passenger Loop on the Sectional Appendix, and I'm sure I've seen it described as Kennet Down Goods Loop somewhere, not sure where!

 

I have a vague memory that this was originally an Up Loop, and that at some time (1970s ?) the Relief Lines were slued and it became a Down Loop ! Clearly the layout has been altered again to put it between the Relief Lines. 

 

[Oldddudders]

No sweat in modern-ish signalling. In 1976 the new London Bridge scheme included a fully reversible line, 2 RVL,  between London Bridge and North Kent East Junction. It had a Direction of Flow indicator at several points on the panel. 

 

I think there may be something similar between Slough and Iver. My budget in 1989/90 included provision for it, but whether it was ever installed I know not, as I had moved on. 

[The Stationmaster]

14 hours ago, St. Simon said:

 

Hi Phil,

 

Yep, there is a loop between the Up and Down Reliefs, although it is described as Kennet Loop on the signalling plan, but Kennet Passenger Loop on the Sectional Appendix, and I'm sure I've seen it described as Kennet Down Goods Loop somewhere, not sure where!

 

The Loop is sort of Bi-directional, both Up and Down Direction trains can enter it, but only Down Direction trains can leave it. . Up Direction Trains can enter the loop from any of the four lines on the country side, but are stopped by a squat fixed red at the London end of the loop. It is primarily used for storing trains turning back at Reading to save Platform Space (although generally not very often and even then only for a few minutes), freight can be looped in there, but I think the preference is to hold freights on the country side of Reading, as there's more space.

 

Simon

Yes.  Kennet Goods Loop was the previous loop and was commissioned in Stage 1 of the Reading - Hayes MAS scheme (Reading ML East - Twyford) over the weekend of 11 -13 February 1961.  It replaced the Down Refuge Siding at Sonning Sidings.  The footprint for the new loop was created by widening the north side embankment towards the river and the Up Relief was slewed on to the new embankment - where it subsequently partially gave way under a Pressed Steel dmu which was only saved from going down the bank by an adjacent signal post.  The previous Up Relief was reconnected at each end to become the Down Relief and the previous Down relief became the Down Goods Loop.

 

In the more recent Reading alterations things were changed again and the Down Loop (relaid at long last) became the Down Relief while the Down Relief became the new passenger loop (which I have actually travelled over in a passenger train on one occasion).  Thus the Down Relief is back where it was prior to February 1961 and what was the Up Relief back then is now the site of the current passenger loop.

 

Noting 'Olddudders' comment the various Slough - Iver proposals came to naught.  What had been proposed there was to reinstate the former Up Goods Line between Dolphin Jcn and Langley and make it the Up Relief while turning the existing Up Relief into a bi-directional line between the Up & Down Reliefs.  I know that one of the ideas envisaged taking this arrangement through to Iver (which would mean demolition of Langley station building) plus rebuilding the overbridge west of Langley as well as embankment widening but I don't know if that part was ever a really serious idea.  A similar sort of idea was also talked about for Iver to West Drayton in connection with Crossrail with the existing Up Goods becoming the Up Relief and the former Up Relief becoming a bi-directional line - I've an idea that one might even have got a mention in 'Modern Railways'.  Neither of them were really practicable ideas because it was very easy to prove (which I did for the latter one) that the distances involved were far too short for dynamic overtaking or even dynamic looping of a freight train which is what the proponents of the idea were suggesting.  Making it a bi-directional goods loop would have made a bit more sense but the time cost fira. freight train would have been less than palatable.

[The Stationmaster]

15 hours ago, H2O said:

I used to think that the central lines between the platform lines at Bath and Chelmsford were 'avoiding' lines to hold a slower train or let faster non-stop services pass stopping ones. However in the signal box diagrams I have seen in both cases they were connected as long trailing crossovers. Were they alway like that or were they ever used as loops?

What existed at Bath was a common arrangement on the GWR which at one time existed at numerous places and was basically a double ended siding connected at each end to a running line by a trailing point.  Reading, I think probably had the last example although its use had changed enormously over the years.   All the three track bits of running line on the Western which I can think of were strictly uni-directional for the third line.

[Mike_Walker]

30 minutes ago, The Stationmaster said:

Yes.  Kennet Goods Loop was the previous loop and was commissioned in Stage 1 of the Reading - Hayes MAS scheme (Reading ML East - Twyford) over the weekend of 11 -13 February 1961.  It replaced the Down Refuge Siding at Sonning Sidings.  The footprint for the new loop was created by widening the north side embankment towards the river and the Up Relief was slewed on to the new embankment - where it subsequently partially gave way under a Pressed Steel dmu which was only saved from going down the bank by an adjacent signal post.  The previous Up Relief was reconnected at each end to become the Down Relief and the previous Down relief became the Down Goods Loop.

 

In the more recent Reading alterations things were changed again and the Down Loop (relaid at long last) became the Down Relief while the Down Relief became the new passenger loop (which I have actually travelled over in a passenger train on one occasion).  Thus the Down Relief is back where it was prior to February 1961 and what was the Up Relief back then is now the site of the current passenger loop.

 

Noting 'Olddudders' comment the various Slough - Iver proposals came to naught.  What had been proposed there was to reinstate the former Up Goods Line between Dolphin Jcn and Langley and make it the Up Relief while turning the existing Up Relief into a bi-directional line between the Up & Down Reliefs.  I know that one of the ideas envisaged taking this arrangement through to Iver (which would mean demolition of Langley station building) plus rebuilding the overbridge west of Langley as well as embankment widening but I don't know if that part was ever a really serious idea.  A similar sort of idea was also talked about for Iver to West Drayton in connection with Crossrail with the existing Up Goods becoming the Up Relief and the former Up Relief becoming a bi-directional line - I've an idea that one might even have got a mention in 'Modern Railways'.  Neither of them were really practicable ideas because it was very easy to prove (which I did for the latter one) that the distances involved were far too short for dynamic overtaking or even dynamic looping of a freight train which is what the proponents of the idea were suggesting.  Making it a bi-directional goods loop would have made a bit more sense but the time cost fira. freight train would have been less than palatable.

I'm not sure this correct.  I've reviewed the NR Scheme Plans for the Reading project (I prepare train crew route diagrams for GWR and other TOCs) which make no reference to altering the alignments of Relief lines and Loop at any stage during the project only alterations to the signalling and designations.  On scheme plans, new works are shown in red, items to be recovered in green and unaltered remains black.  On all stages the lines in question are shown in black and, personally, I don't recall the present layout being changed at any time during the works.

 

Regarding the Slough - Iver area back in 2014 Mark Hopwood and I drew up a scheme to provide a 5 track passenger railway all the way from Farnham Road (west of Slough) all the way to Hanwell Bridge Junction.  The additional line would have been on the Up or north side and would require considerable rebuilding of all the stations and many bridges although replacing the Wharncliffe Viaduct was seen as a step too far!  The idea was to provide additional capacity to accommodate Crossrail and would make the present Up Relief bi-directional  with "tidal flow" operations, used for Up trains in the morning peak, Down in the evening.  It was submitted to NR by GWR as part of bids for CP6 but failed to fly.

 

[Harlequin]

8 minutes ago, The Stationmaster said:

What existed at Bath was a common arrangement on the GWR which at one time existed at numerous places and was basically a double ended siding connected at each end to a running line by a trailing point.  Reading, I think probably had the last example although its use had changed enormously over the years.   All the three track bits of running line on the Western which I can think of were strictly uni-directional for the third line.

Could the central siding of the type described have been used to allow passing by having the train ahead setting back into it, assuming it was not used to hold rolling stock?

 

(BTW: A bi-directional central loop, as the OP imagines it, would need facing points at both ends, signalling and multiple FPLs so quite a complex and expensive bit of infrastructure. In fact, quite expensive in terms of space in a model too...)

 

Edited February 23, 2021 by Harlequin

[Oldddudders]

48 minutes ago, The Stationmaster said:

Noting 'Olddudders' comment the various Slough - Iver proposals came to naught.  What had been proposed there was to reinstate the former Up Goods Line between Dolphin Jcn and Langley and make it the Up Relief while turning the existing Up Relief into a bi-directional line between the Up & Down Reliefs.  I know that one of the ideas envisaged taking this arrangement through to Iver (which would mean demolition of Langley station building) plus rebuilding the overbridge west of Langley as well as embankment widening but I don't know if that part was ever a really serious idea.  A similar sort of idea was also talked about for Iver to West Drayton in connection with Crossrail with the existing Up Goods becoming the Up Relief and the former Up Relief becoming a bi-directional line - I've an idea that one might even have got a mention in 'Modern Railways'.  Neither of them were really practicable ideas because it was very easy to prove (which I did for the latter one) that the distances involved were far too short for dynamic overtaking or even dynamic looping of a freight train which is what the proponents of the idea were suggesting.  Making it a bi-directional goods loop would have made a bit more sense but the time cost fira. freight train would have been less than palatable.

Yes, the item in NSE's RailPlan was "Slough-Iver & Dynamic Loop" I think. My then boss, Chris Tibbits, had previously been Network Manager, Thames & Chiltern, so he knew the importance. But the 1990 economic downturn caused quite a number of schemes to be deferred, and, even if this one had been a runner, by the time income was on the up again, Privatisation was under way, and the Board was being limited in its investment plans. Crossrail was then merely a twinkle in a few eyes, but Don Heath, formerly BR Director, Projects, had been sent to join the Crossrail team to head-up the BR input. 

[St. Simon]

1 hour ago, Mike_Walker said:

I'm not sure this correct.  I've reviewed the NR Scheme Plans for the Reading project (I prepare train crew route diagrams for GWR and other TOCs) which make no reference to altering the alignments of Relief lines and Loop at any stage during the project only alterations to the signalling and designations.  On scheme plans, new works are shown in red, items to be recovered in green and unaltered remains black.  On all stages the lines in question are shown in black and, personally, I don't recall the present layout being changed at any time during the works.

 

Hi,

 

Most scheme plans don't tend to show red / green work for slews or altering alignments (although some designers do put it on there, but I personally think it looks messy), as signalling designers don't care whether the track is being moved a few inches to the left or right, we just care that the track is there! 

 

We only really show alignment alterations if that is the purpose of any signalling works.

 

Simon

[Compound2632]

20 hours ago, MickeyMoggs said:

Working in a limited space (aren't we all) and was wondering if anyone was aware of a prototype where where an Up line and and Down line shared a passing loop, or would it have been completely forbidden in steam practice (esp. GWR)? ie, two lines in, three lines for a distance than back down to two, with both lines being able to access the central "loop". Many thanks in advance.

 

On the assumption that your enquiry is about Great Western practice, or steam era in general, and assuming that what you want is a lie-by for goods or mineral trains to be passed by fast trains, then a much more probable arrangement is a loop to one side of the running lines with trailing connections in each direction - essentially a bi-directional siding into which the train is reversed. No facing points in the running lines. If modelling post-war, it's possible that a facing connection could have been put in as a wartime improvement, for one direction only - e.g. if the loop is on the down side of the line, it has been converted to a running loop for down trains but can still act as a lie-by for up trains. 

 

But I think in either case a more typical arrangement would be to have a lie-by siding on each side of the running lines, so that an up train didn't have to block the down line while backing in. Both could have been converted to loops during the war. The first arrangement I described is more typical of a goods yard at a wayside station, where access is required from either direction of running line.

 

Where one could find a common lie-by between running lines would be between the pairs of lines of a four-track section, if the lines were arranged in pairs: up and down fast, siding between the down fast and up slow, up and down slow. But still facing points in the running lines would be avoided.

 

(All the other replies appear to be about contemporary practice, which is very different. About the only thing the modern railway has in common with the steam age railway is some earthworks. It's like saying the A5 is a Roman road.)

Edited February 23, 2021 by Compound2632

[DY444]

Highbridge loop is one example.