Increasing throughput of trains - some ways of doing it

[whole diary]

[grahame]

In another thread ({here}) I documented / described the solution adopted an Penryn on the Falmouth branch for increased capacity.   Doubt has been expressed at the robustness of such an arrangement for a line that's got the potential to be disrupted at both ends ... so here (separate thread) is a list of the various things I can think of that could be done to increase capacity.   Not an expert, so some may be silly and my list may not be complete ...

1. Closer crossover to Thingley Junction
2. Faster junction pointwork
3. Intermediate signals
4. Intermediate loop near but not at Melksham
5. Intermediate loop at Melksham
6. Double junction(s) at Thingley and / or Bradford
7. Double junction(s) with sufficient double track to hold a train off main line
8. Holding loops just off the main lines at Thingley and / or Bradford
9. Dynamic loop(s) between River Avon and Melksham, and Melksham and Thingley
10. Redouble from River Avon to Thingley with "Malton" platform at Melksham
11. Redouble from River Avon to Thingley with two platforms at Melksham
12. Redouble the whole line

[JayMac]

13. Redouble whole line with grade separation at Thingley Junction.

[SandTEngineer]

Grahame.  What is the issue with the river Avon bridge that would stop double track being restored across it?

[martyjon]

13. Redouble whole line with grade separation at Thingley Junction.

.... and reinstate a single line Bradford North curve, not so sure about grade separation at Thingley though. 

[Adelante_CCT]

14. Four Track, Now!

[grahame]

Grahame.  What is the issue with the river Avon bridge that would stop double track being restored across it?

I stand open to correction, but I think the double track bridge there may have been replaced by a single track one?   Now that you ask, I'm not so sure.   But it's the major engineering element on the line ...

[grahame]

13. Redouble whole line with grade separation at Thingley Junction.

.... and reinstate a single line Bradford North curve, not so sure about grade separation at Thingley though. 

This idea always worries me as we could end up splitting our southbound service between two destinations, both of which are running not quite frequently enough for them to be virtually a turn up and go service.

You could, however (once you've doubled the track to add capacity) restore both the Bradford East - West and the Thingley South - West curve and then save yourself the Bathampton turn back for MetroWest by running  Bristol Temple Meads, stations to Bath - Corsham - Melksham - Bradford-on-Avon - Avoncliff - Freshford - Bath and stations to Bristol Temple Meads.  I expect that would be very popular and would generate far more revenue that just running the Bath terminator to Westbury putting that up to 3 per hour; Trowbridge and Westbury would probably benefit far more from longer trains than more of them.

[SandTEngineer]

Grahame.  What is the issue with the river Avon bridge that would stop double track being restored across it?

I stand open to correction, but I think the double track bridge there may have been replaced by a single track one?   Now that you ask, I'm not so sure.   But it's the major engineering element on the line ...

OK.  I have had a look on GOOGLE MAPS and as best I can see the bridge still looks to be double track width with the current single line slued to the middle of it.

On that basis, I would vote for No.10 (the option that is, not the Downing Street one..... )

[LiskeardRich]

Cost wise  something like penryn may be a lowest cost option and more easily justifiable?

[martyjon]

13. Redouble whole line with grade separation at Thingley Junction.

.... and reinstate a single line Bradford North curve, not so sure about grade separation at Thingley though. 

This idea always worries me as we could end up splitting our southbound service between two destinations, both of which are running not quite frequently enough for them to be virtually a turn up and go service.

You could, however (once you've doubled the track to add capacity) restore both the Bradford East - West and the Thingley South - West curve and then save yourself the Bathampton turn back for MetroWest by running  Bristol Temple Meads, stations to Bath - Corsham - Melksham - Bradford-on-Avon - Avoncliff - Freshford - Bath and stations to Bristol Temple Meads.  I expect that would be very popular and would generate far more revenue that just running the Bath terminator to Westbury putting that up to 3 per hour; Trowbridge and Westbury would probably benefit far more from longer trains than more of them.

I was thinking more of a re-instated Bradford North curve acting as a diversionary route when Bathampton to Thingley is closed for engineering works or other times when the direct route is unavailable for traffic.

[Bmblbzzz]

If you were going to have MetroWest running in a loop like that using a new line at Thingley, why not just send it on a few more miles to Chippenham and reverse there using a third platform (and then the rest of that loop)?

[stuving]

OK.  I have had a look on GOOGLE MAPS and as best I can see the bridge still looks to be double track width with the current single line slued to the middle of it.

Funny. When I ask Google Earth to measure the width of that bridge, it tells me 4.2m - and a train is over 3.2 m wide before clearances. So definitely single track.  By comparison, there's an accommodation track under the line just to the north-east, with parapets 8.2 m apart.

Now, have any other over- or underbridges on that stretch been renewed since singling and without preserving the double-track width?

[ellendune]

Ok so what is a "Malton" platform then?  I have heard of a different platform arrangement at Penmere.  

[grahame]

Ok so what is a "Malton" platform then?  I have heard of a different platform arrangement at Penmere.  

A double track line but a platform on one line only on the "up" line.  Down line trains cross over as they approach the station via a facing crossover, and cross back upon departure through another crossover.

[grahame]

Ok so what is a "Malton" platform then?  I have heard of a different platform arrangement at Penmere.  

A double track line but a platform on one line only on the "up" line.  Down line trains cross over as they approach the station via a facing crossover, and cross back upon departure through another crossover.

I should add that the option is to replicate the current Malton, not the old one.   From Wikipedia:

Though Malton station now has only one platform in use, at its peak, there were two through platforms and an additional bay platform serving (mainly) Whitby local trains. The George Townsend Andrews overall roof was removed in 1989 and replaced by the canopy recovered from the Whitby platform.

One of Malton station's claim to fame was the novel solution adopted to allow passengers to access the second (island) platform, instead of a footbridge or barrow crossing the NER installed a removable section of platform, in the form of a wheeled trolley running on rails set at right-angles to the (single) running line. When a train had to use the platform, the trolley was wheeled back under the up (York) platform; the trolley was interlocked, with the signals giving access to the platform.

After which I should start drawing a parallel to the turning arrangement at Brockenhurst for wheelchairs. Is that still in use?