Where is passive provision being made in resignalling and electrification?

[whole diary]

[grahame]

There would appear to be room on railway land for quote a long loop to the south of the Bristol bound line at Chippenham, starting from (at the west end) a three coach train alongside the currently disused platform and continuing up to and beyond the Calne branch alignment.  This would seem to fit in with various "Doorway Chippenham" plans too.    There are, however, various old (?) signalling things on that alignment.

Does anyone on the "inside" know whether resignalling and electrification through Chippenham makes passive provision to protect this alignment should a loop and crossovers be required in the lifetime of the new works soon to be done?   I have asked Network Rail at two of their road shows, and not received a definite answer (rather, I have received contradicting indications).  I'm also finding myself referred to Wiltshire Council and the Local Transport Board with a comment that their inputs will have been allowed for in whatever's being done - however, I'm having some difficulty finding anything along those lines relating to theSwindon and Wiltshire LTB.

A loop at Chippenham would allow for extra robustness for freight and passenger trains headed south, which currently block the main line if the single line from Trowbridge is blocked.  It would also allow for practical turnbacks for (say) an extra Bristol -> Bath local extended to Chippenham (saving the cost of a Batheaston turn back), for slower trains to be overtaken by expresses, so that a Bristol - Oxford service could pause for a new minutes while a Bristol - London went past.   In this way, it's enabling a service that supports aspirations at Corsham, Royal Wootton Bassett and Wantage Road.

[grahame]

Here is some official description of the Chippenham plans  - in the FGW^▸ (First Great Western) "Station News" I picked up at Swindon





You'll note funding plans already made.

Here's an overview of what it might look like:



Key
Black - current
Green - initial proposal; new station building and multi story car pack spanning the tracks, accessible link to platform
Blue - first (minimal) proposal to add old platform access for turn back for Bristol Metro and perhaps other trains
Red - additional proposal to deliver much more for the future, as outlined in earlier post.

I seem to have met a deafening silence to my question "what passive provision is being allowed at Chippenham" ... perhaps it's time to start pressing the question more thoroughly?

[John R]

I'd suggest the blue proposal could be even more minimalist. Why go to the expense of a crossover when there's a perfectly good one a mile to the west?

[Oberon]

I suspect Ms Claire Perry might be someone worth sounding out for this scheme. She's bound to have at least a passing interest even though Chippenham is not her constituency. Be quick though, May 2015 is  not that far away!

And whilst we're on the subject of small schemes that would make a lot of difference, does anybody know if Westbury's long awaited 4th platform face might ever see the light of day?

[eightf48544]

I'd suggest the blue proposal could be even more minimalist. Why go to the expense of a crossover when there's a perfectly good one a mile to the west?

just to point out that one of the problems od modern track layouts is the failure to put crossovers where required. It would be better to have the crosover at the end of the loop to prevent a mile of wrong line working for up trains which takes time and cuts paths for Down trains. Also the loop crossover could be a slow speed one as trains would be either decellerating or accelerating from the station.

[John R]

The blue proposal isn't a full loop - just a spur into a newly reopened platform.  As such, I'd suggest a crossover would be excessive, and would probably triple the cost, particularly when the additional signalling complexity is taken into consideration.  The current line is bidirectional, so the signalling changes would be (relatively) straightforward.

Much better to get something down and proving its worth. The option wouldn't do anything to preclude a crossover at a later stage, although I'm not convinced it would even be needed for the red option, as the loop would typically be used by down services only.

[ellendune]

The blue proposal isn't a full loop - just a spur into a newly reopened platform.  As such, I'd suggest a crossover would be excessive, and would probably triple the cost, particularly when the additional signalling complexity is taken into consideration.  The current line is bidirectional, so the signalling changes would be (relatively) straightforward.

Much better to get something down and proving its worth. The option wouldn't do anything to preclude a crossover at a later stage, although I'm not convinced it would even be needed for the red option, as the loop would typically be used by down services only.

It could be more than a loop it could be a turn back siding with the appropriate crossover

[John R]

Agree, a turn back siding is what is meant, but it doesn't need an expensive crossover as there's a perfectly good one a mile further west at Thingley East. At some point a unit approaching from the west needs to cross the down line and block it, so using the existing facility would only add about 90 secs to the time. It's not so heavily used a line that would be an issue. 

[grahame]

Agree, a turn back siding is what is meant, but it doesn't need an expensive crossover as there's a perfectly good one a mile further west at Thingley East. At some point a unit approaching from the west needs to cross the down line and block it, so using the existing facility would only add about 90 secs to the time. It's not so heavily used a line that would be an issue. 

The thead asks about passive provision - in other words about signalling and engineering works to be done in such a way that they'll need to be reversed / undone / expensively modified, rather than necessarily doing all the protected work earlier on.   Taking a leaf our of Network Rail's Route Study, that has us looking forward by 30 years.  And where we currently have around 6 trains an hour passing through Chippenham (4 London - Bristol trains, 1 TransWilts passenger and 1 TranwWilts freight), we may have many more (4 London - Bristol trains, 2 TransWilts Passenger, 2 East-West - Bristol, 2 Bristol Metro, 4 freight - total 14).   You may argue as to if this might happen, but it's not beyond the realms of possibility  ... and if you find it hard to see in 30 years, look to 50.     We don't want to be the ones who stood aside as things were done to find a boating lake or a block of council offices blocking our economic development.

[eightf48544]

Graham to answer your question re passive provision unfortunately Network Rail is still sufferring form the sacking of most of the in house BR^▸ (British Rail(ways)) engineers by Railtrack thereby losing the collective memory built up by BR from the original London Manchester/Liverpool electrification. Therefore, they are having to learn how to electrify a mainline from scratch with few people to give guidance from that collective memory.

Therefore, it is possibly over optimistic to expect that future provision can be built in whilst the rush is on to sling teh wires and resignal the GMWL. Which is unfortunate as a little thought could easily position equipment to allow for futher track work in future.

[4064ReadingAbbey]

Graham to answer your question re passive provision unfortunately Network Rail is still sufferring form the sacking of most of the in house BR^▸ (British Rail(ways)) engineers by Railtrack thereby losing the collective memory built up by BR from the original London Manchester/Liverpool electrification. Therefore, they are having to learn how to electrify a mainline from scratch with few people to give guidance from that collective memory.

I'm not sure that that is completely true. Railtrack did not sack any engineers - the ones in question were part of the Civil and Electrical engineering departments which were sold to existing external companies. They may have been TUPEd, but they weren't sacked. And those organisations which were responsible for the day-to-day maintenance have since been bought back by Network Rail.

In any event, corporate memory only exists within the heads of those there now. As the London Manchester/Liverpool electrification was completed nearly 50 years ago the participants are either retired or dead. And there have been electrification programmes since then: the extension to Scotland 10 years later, the Bedpan scheme, the East Coast Main Line and that to Norwich, so there must be some residual knowledge present quite apart from that in the heads of the people who maintain all this kit.

However any passive provision for future works doesn't solely depend on the engineers executing the work, but on those organisations and people who specify the work to be done. Obviously the engineers will design a system to meet the specifications and at the same time try to minimise the costs (purchase costs, installation costs and on-going maintenance costs), but if the specification says 'leave room for another track' then that is what they will do.