How would you quadruple Didcot-Oxford?

[Meerkat]

Has a rough plan been drawn up?
I assume you would keep the fast lines on the East side, though whether they are the new lines or the old slows will vary on location.
Go through the current Appleford station and build a new one on new west slows.
Culham is tricky with a listed old station building. Might be easier to cut the corner with four new tracks to the West if that is possible without replacing the Thames bridge.
Radley - i would suggest moving this south with new road access to make a better Abingdon Parkway.
What do you do at the Oxford end, a flyover to get the slows in the middle for freight to take the through lines? A future Science Park service causes a problem....
What happens at Didcot currently, do the freight trains take the avoiding lines or go through the station to leave them clear?

All this is going to be pricey...how much gain will there be?

 

[swt_passenger]

There’s a few pages about this in the Western route study, starts at about page 147.
Too much to copy I think.
https://cdn.networkrail.co.uk/wp-content/uploads/2016/11/Western-Route-Study-Final-1.pdf
Surprisingly, (to me), they actually seem to suggest a “paired by use” layout through Oxford, with Banbury and Cotswolds services on the western island, and EWR & Chiltern on the eastern island. This apparently avoids grade separation at Oxford North. It’s not made clear what would happen at intermediate stations, but suggests to me a new Fast pair on the down side, with stoppers connected to EWR...

 

[si404]

It’s not made clear what would happen at intermediate stations, but suggests to me a new Fast pair on the down side, with stoppers connected to EWR...

Which would lead to issues at Didcot with the fast tracks and slow tracks needing to swap over so stoppers can serve Didcot and fast services can use the avoiding curve.

 

[swt_passenger]

Which would lead to issues at Didcot with the fast tracks and slow tracks needing to swap over so stoppers can serve Didcot and fast services can use the avoiding curve.

Yes, it definitely suggests all the big changes would be at Didcot, doesn’t it. Perhaps Cotswolds, XC and freight would then use the existing platform lines, and new platforms would be provided for the repositioned reliefs?

As Meerkat mentioned, a drawing would be handy...

 

[Meerkat]

I hadn’t considered EWR! I was assuming quadrupling was needed to speed up fast trains, allowing extra freight and locals to be overtaken.
Are they assuming that all freight will be going to Bletchley? Otherwise there will be crossing moves or freight holding up XC and GWR

 

[swt_passenger]

I hadn’t considered EWR! I was assuming quadrupling was needed to speed up fast trains, allowing extra freight and locals to be overtaken.
Are they assuming that all freight will be going to Bletchley? Otherwise there will be crossing moves or freight holding up XC and GWR

I’m assuming freight would still run on the Cotswold/Banbury pair. Effectively thats where they’d have to be north of Oxford anyway... I don’t think it’s ever been expected that EWR would take all the existing freight?

 

[Meerkat]

I’m assuming freight would run on the Cotswold/Banbury pair. Effectively thats where they’d have to be north of Oxford anyway...

But then they hold up XC and GWR that could otherwise do 125mph on fast lines, and not all those fast trains go to Banbury

 

[swt_passenger]

But then they hold up XC and GWR that could otherwise do 125mph on fast lines, and not all those fast trains go to Banbury

But then don’t they say there’ll be no intention of grade separation at Oxford, so presumably that means the junction between Banbury and Cotswolds routes must still be a conflicting flat crossing anyway.

 

[181]

Culham is tricky with a listed old station building.

Perhaps it could be moved out of the way, like this -- it's a smaller building than that lighthouse.

What happens at Didcot currently, do the freight trains take the avoiding lines or go through the station to leave them clear?

I think they usually use the avoiding line.

 

[jimm]

Has a rough plan been drawn up?
I assume you would keep the fast lines on the East side, though whether they are the new lines or the old slows will vary on location.
Go through the current Appleford station and build a new one on new west slows.
Culham is tricky with a listed old station building. Might be easier to cut the corner with four new tracks to the West if that is possible without replacing the Thames bridge.
Radley - i would suggest moving this south with new road access to make a better Abingdon Parkway.
What do you do at the Oxford end, a flyover to get the slows in the middle for freight to take the through lines? A future Science Park service causes a problem....
What happens at Didcot currently, do the freight trains take the avoiding lines or go through the station to leave them clear?

All this is going to be pricey...how much gain will there be?

In terms of gain, a lot, by keeping all the container trains (of which yet more are anticipated to run in the future) out of the way of fast passenger trains between Didcot and Oxford - I can't see what pairing by destination is supposed to achieve, other than a mess - while grade separation at Didcot would provide plenty of gain for both Oxford line services and those on the GWML by eliminating lots of the current conflicting moves on the flat at Didcot East junction).

From Appleford level crossing past Culham, a pair of new tracks a decent distance to the west of the existing formation would probably be the best solution - there is a stretch of water just to the west of the railway though Appleford, which is parallel to the line but hidden behind a line of trees, while at Culham, as well as the listed Brunel station, there is the Railway Inn just west of the line at the south and of the station - though how much land there will be to play with here remains to be seen, as there is a proposal to build lots of new houses in the fields between the station and Culham village, which is just to the west.

Radley is not going to be a great deal of use as anything more than a village station unless it gets many more trains calling than now - and a lot of money has just been sunk into a new multi-storey car park at Didcot Parkway. Now if the burghers of Abingdon had been more receptive to Brunel's approaches in the 1830s, things might have turned out differently and Didcot would still just be a farming hamlet and Abingdon the place with lots of trains in all directions.

Freights at Didcot go wherever is best for them - some use the avoiding line, others go into the yard for staging/crew changes, or via the station lines just to get them out of the way of GWR or XC fasts.

I'd suggest grade separation at Didcot, and some signalling changes, are likely to be a higher priority for action than quadrupling, especially if money for big investments remains tight well into the future.

 

[Meerkat]

I guess the issue is that without a decision that there will be no quadrupling or that it will be off route then there will be no electrification.

 

[didcotdean]

A corridor running to the west of Appleford between the A4310 and A415 is also Oxfordshire County Council's preferred alignment for a new road between north Didcot and Culham, so there certainly is a lot to fit in.