Will there come a time when service ambitions and performance issues require another two tracks between Yate and Bristol Parkway to segregate Cross Country and local services from the GWR London expresses?
A thought-provoking post. For what it’s worth, here’s my two pennies worth.
Although a new more direct XC route west of Yate would reduce journey times it would be hugely expensive. Also, the GWML between Bristol Parkway and Swindon is direct and well aligned and doesn’t need replacement. However, that’s not to mean that a good case cannot be made for other targeted upgrades.
Currently 5tph ply in each direction between Bristol Parkway and Westerleigh Junction a few miles to the east.
GW South Wales to London 2tph
GW Bristol to Cheltenham 1tph
XC Bristol to Birmingham 2tph
However, there are plans for
additional services. To the best of my knowledge, these comprise the following:
GW Bristol to London (via BPW) 2tph GWML electrification
GW Bristol to Yate 1tph Avon Metro
XC Bristol to Birmingham 1tph Midland Rail Hub
XC South Wales to Birmingham 1tph Midland Rail Hub
If these aspirations are met, then it represents a doubling in the volume of passenger services between Bristol Parkway and Westerleigh Junction and, as you rightly suggest, raises the question of whether the existing infrastructure can provide the necessary capacity.
I’m no expert but I’d hazard the following thoughts….
- Bristol Parkway (BPW) itself, with 2 island platforms providing 4 platform faces should be enough to cater for the expected 10tph in each direction.
- Stoke Gifford Junction, immediately to the west of BPW, though busy will be operating within capacity due to the low speeds as all passenger services stop at BPW.
- With modern signalling the two-track GWML running east from BPW to Westerleigh Junction will also be within capacity and not require quadrupling.
- Westerleigh Junction is the only weak link. With twice as many XC and Regional services merging across a flat junction with twice the number of GWR Expresses, the potential for conflict increases four-fold. Two solutions spring to mind.
The least intrusive option would be to upgrade the existing junction to increase its capacity. This could be achieved by adding a third “holding” track for XC services. A new GW Main Down line could be constructed a few metres south of the existing one, starting a couple of hundred metres east of Westerleigh junction and tapering into the existing line say half a mile west of the junction. Currently XC services can only join the GWML if the line is clear in both directions. This new arrangement would enable trains to proceed onto the junction if the Up Line was clear, but the Down Line was occupied. In this case XC services would wait in what is currently the Down Main until the line ahead was clear.
A more ambitious option would be to abandon the existing junction completely and build a brand new fully grade separated junction a mile or so further west. This would involve new approach tracks curving gently westwards from just south of Yate Station. This alignment would be slightly shorter, conflict free and support much faster running. I don’t think it would involve much if any demolition and hopefully, not too much opposition.
I may have got this completely wrong, but I would be surprised if the recently upgraded rail infrastructure around the Bristol Parkway area wouldn’t be able to comfortably handle double current traffic volumes. The only caveat - a new Westerleigh Junction would be essential to unlocking that capacity.
