Track design

[Inversnecky]

Are there any informative resources about track design (thinking of in urban areas and station vicinities)? How switches, slips and crossings are organised and laid out? Are the more complex elements built are required, or do they generally simpler if space allows?

As a child I was always amazed at the complexity on some routes. And wondered if there was a ‘design manual’.

 

[Tom Quinne]

I’ve always wondered how the designers work out how many switches and crossings they need and where.

Looking at the workstations I work there’s some glaring omissions where a point end could open up huge flexibility, but I assume layouts are built to a cost not operational flexibility.

 

[Ianno87]

There did happen to be a good Twitter thread on this a few days ago: https://twitter.com/WilliamBarter1/status/1344965459725197315

 

[coppercapped]

The Permanent Way Institute https://www.thepwi.org may well have some of the information you want.

 

[The Planner]

I’ve always wondered how the designers work out how many switches and crossings they need and where.

Looking at the workstations I work there’s some glaring omissions where a point end could open up huge flexibility, but I assume layouts are built to a cost not operational flexibility.

A lot of it comes from the initial timetabling work, @Ianno87 will have the scars. A layout will be suggested to deliver the proposed service, that then gets whittled away as you suggest during development due to things not being able to fit in the space, signaling issues, cost etc..

 

[CEN60]

Network Rail have a Track Design handbook, plus the PWI do a series of handbooks on various subjects covering S&C etc - however after 30 odd years of doing it you get a feel for it!!!!!!! However - modern software is dangerous - just because the software will do it doesn't mean you can!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Inversnecky]

There did happen to be a good Twitter thread on this a few days ago: https://twitter.com/WilliamBarter1/status/1344965459725197315

thanks to all for the replies. That was an interesting thread.

I’m a little confused by what is meant by ‘parallel moves’: I can’t quite work it out from the diagrams he posted.

The Permanent Way Institute https://www.thepwi.org may well have some of the information you want.

Cheers, will have a look.

This was an interesting old video I came across over the holidays:

One thing I notice is that track work around stations has been simplified in recent decades: presumably as a result of fewer routes (Beeching) and fewer trains? Or perhaps improved planning of train movements also made some crossings redundant?

 

[edwin_m]

I’m a little confused by what is meant by ‘parallel moves’: I can’t quite work it out from the diagrams he posted.

Parallel moves are when enough tracks are provided for two trains to pass over a track layout between the same start and finish routes at the same time, though not necessarily in the same direction. So for example at Euston there can be simultaneous departures from high-numbered and low-numbered platforms, that have totally separate routes and end up on the Down Fast and the Down Slow at Queens Park.

 

[Ianno87]

Parallel moves are when enough tracks are provided for two trains to pass over a track layout between the same start and finish routes at the same time, though not necessarily in the same direction. So for example at Euston there can be simultaneous departures from high-numbered and low-numbered platforms, that have totally separate routes and end up on the Down Fast and the Down Slow at Queens Park.

The diagram in this Tweet (https://twitter.com/WilliamBarter1/status/1344969509963231234) is a good example:

A train can depart Platform 1 and arrive Platform 2 at the same time
As can a train Platform 2/3, and also Platform 3/4, etc.

However, if the scissors crossovers off the end of Platform 2/3 were removed, Depart Platform 1/Arrive platform 2 would not be possible with a parallel move, nor would Depart Platform 3/Arrive platform 4 be either.

 

[Ploughman]

This topic is really dependant on 2 aspects of Track Design.

The Track Design Manual mentioned above relates to the physical layout of actual track, what can be done with it and limitations that must be worked to. This will determine Track Curvature, Cants, Gradients, Rates of change and Clearances.

The other aspect is Designing a layout to cater for the required traffic.
Where the Traffic is coming from and where it is going.
Capacity, Flexibility and future trends willl be factors in this.

 

[Gloster]

One thing I notice is that track work around stations has been simplified in recent decades: presumably as a result of fewer routes (Beeching) and fewer trains? Or perhaps improved planning of train movements also made some crossings redundant?

There is also far more use of multiple units, cleaning a rake of coaches in the platform before sending them out on another service (rather than using a pilot to haul them out to the carriage sidings), and far less intermediate shunting of vehicles on and off trains. Fewer and less varied movements reduce the need for routes in the station area.

 

[Ianno87]

There is also far more use of multiple units, cleaning a rake of coaches in the platform before sending them out on another service (rather than using a pilot to haul them out to the carriage sidings), and far less intermediate shunting of vehicles on and off trains. Fewer and less varied movements reduce the need for routes in the station area.

And fewer routes often means that the remaining routes can be faster (by having to squeeze less stuff into the same space) , so platform reoccupation margins can be improved.

 

[edwin_m]

Also the better acceleration of modern trains means it's possible for station throats to have fewer but faster switches and crossings. Each train takes less time to pass over the pointwork, which offsets the reduced flexibility for parallel moves.

 

[John Webb]

One thing I notice is that track work around stations has been simplified in recent decades: presumably as a result of fewer routes (Beeching) and fewer trains? Or perhaps improved planning of train movements also made some crossings redundant?

Simplifying trackwork also reduces maintenance costs and eases fault corrections.

One book which explains something of the various factors, admittedly aimed at railway modellers, is "Railway Signalling and Track Plans" by Bob Essery, published by Ian Allan in 2007, ISBN 0 7110 3215 7.

 

[EveningStar]

If you are looking for the history of track design, Andrew Dow's book, 'The Railway', is a worth a look.

 

[Gostav]

I am very curious who designed the old Newcastle station junction and in my opinion, it seems that British railways use too many level crossings.

 

[Inversnecky]

Also the better acceleration of modern trains means it's possible for station throats to have fewer but faster switches and crossings. Each train takes less time to pass over the pointwork, which offsets the reduced flexibility for parallel moves.

I was always struck by the simplification of the tracks into Edinburgh Waverley.

 

[Ianno87]

I was always struck by the simplification of the tracks into Edinburgh Waverley.

Simplification also makes it much less complex to electrify.

 

[mcmad]

Arguably Waverley, particularly the East End has been over simplified and now struggles to cope with the moves required. Even the West end has a fair number of platforms only accessible from one of the approach lines.

 

[edwin_m]

Arguably Waverley, particularly the East End has been over simplified and now struggles to cope with the moves required. Even the West end has a fair number of platforms only accessible from one of the approach lines.

Some of the schemes of the 80s took things too far. York and Newcastle probably got it about right but most of the rationalisation at Leicester has been put back or is being talked about, and the deficiencies of the signalling at Crewe have been discussed at length on here.

 

[Bald Rick]

As mentioned above, the PWI have text books on the subject; the S&C design text book is here:

The Permanent Way Institution

www.thepwi.org

Whilst it’s 20 years old, the principles it explains still stand. It’s effectively a slightly easier to understand explanation of the relevant engineering standards. It’s not cheap.

The full list of books available from the PWI is here.

The Permanent Way Institution

www.thepwi.org

I have a view that everyone involved in the development of railway projects should have a copy of the S&C book and the plain line maintenance book. But I’m old fashioned like that.

 

[furnessvale]

Some of the schemes of the 80s took things too far. York and Newcastle probably got it about right but most of the rationalisation at Leicester has been put back or is being talked about, and the deficiencies of the signalling at Crewe have been discussed at length on here.

Things can also go wrong. A remodelling of Preston in the early 1970s allowed for no engine movements for loco changing on Blackpool, Liverpool and Manchester trains as those lines were to be electrified.........over 40 years later, that electrification has been completed.

 

[Bald Rick]

Things can also go wrong. A remodelling of Preston in the early 1970s allowed for no engine movements for loco changing on Blackpool, Liverpool and Manchester trains as those lines were to be electrified.........over 40 years later, that electrification has been completed.

How did those loco changes happen - was it re-remodelled?

 

[Joseph_Locke]

*cough* all those routes are now electrified *cough* (bar Blackpool South, but that service barely has trains, let alone loco-hauled ones)

 

[Ianno87]

How did those loco changes happen - was it re-remodelled?

I must have imagined seeing locomotive changes happening at Preston well into the 1990s.....

 

[Dr Hoo]

Things can also go wrong. A remodelling of Preston in the early 1970s allowed for no engine movements for loco changing on Blackpool, Liverpool and Manchester trains as those lines were to be electrified.........over 40 years later, that electrification has been completed.

This does seem a little strange. O S Nock's definitive book, Electric - Euston to Glasgow makes no mention of any problems despite the fact that Preston acted as the 'changeover' point between electric and diesel on all Anglo-Scottish services from July 1973 (to completion in May 1974).

Nock was, of course, a signalling engineer; even a Past President of the Institution of Railway Signalling Engineers, and he describes Preston: "As a piece of signalling design it is probably without parallel the world over".

(I get that Nock worked for Westinghouse and was hardly likely to describe his company's work as a load of rubbish but really would appreciate a bit more evidence of the supposed problems. I was working on the LM Region at the time and don't recall engine changing being a big issue. Some Liverpool+Manchester-Glasgow+Edinburgh workings had amazing splitting and joining and traction change operations at Preston for years afterwards.)

 

[Bald Rick]

I must have imagined seeing locomotive changes happening at Preston well into the 1990s.....

Exactly! I was on a few of them!

Nock was, of course, a signalling engineer; even a Past President of the Institution of Railway Signalling Engineers, and he describes Preston: "As a piece of signalling design it is probably without parallel the world over".

I’m sure it was in 1974. But then SR, Westinghouse and the Sainted Mr Bell did London Bridge...

 

[Dr Hoo]

I’m sure it was in 1974. But then SR, Westinghouse and the Sainted Mr Bell did London Bridge...

I wouldn't disagree for a moment! Why do you think that I transferred from the LMR in the North West to the South Eastern Division as soon as I could?

 

[Bald Rick]

I wouldn't disagree for a moment! Why do you think that I transferred from the LMR in the North West to the South Eastern Division as soon as I could?

Funny that Preston has outlasted London Bridge. I suspect quite a few Westpac sets made their way north!

 

[furnessvale]

How did those loco changes happen - was it re-remodelled?

No. Loco changing was done, but sub optimally, reducing the capacity of Preston station as a whole.

*cough* all those routes are now electrified *cough* (bar Blackpool South, but that service barely has trains, let alone loco-hauled ones)

Nasty cough you've got there Joseph. Of course those lines are NOW electrified, as I mentioned in my post, 40 years later. Meanwhile, for most of those 40 years loco changing was a sub optimal process eating into station capacity.