TfW to Bristol

[stj]

Once TFW have a full half hourly service which I think is the long term plan when the new stations open i can understand GWR not calling at STJ. I think the Portsmouth's only call at peak time at STJ.

Yes Portsmouths are but Cardiff-Taunton/Penzance Hourly which would mean a change at Temple Meads.Hopefully the London
open access will go ahead too.

 

[John R]

Apologies, Pilning. 20mph Entry and Exit doesn't help with the steep grade as well.

Low entry and exit speeds are generally a big issue in reducing capacity. There was an article in Modern Railways a few months ago discussing this issue as it affects the WCML north of Preston and how maybe the railway is waking up to the problem. Strange really, as it seems blindingly obvious.

== Doublepost prevention - post automatically merged: 8 Sep 2025 ==

I can’t quote from it atm, but worth noting for those who ask what remit TfW has to operate to Bristol Temple Meads that the “operational geography” of TfW includes that route, and that DfT has been heavily involved and has agreed for the proposal to go ahead (section 6.1 of the application).

There was a restriction until Bristol East was remodelled, but DfT has confirmed that restriction no longer applies.

 

[zwk500]

Low entry and exit speeds are generally a big issue in reducing capacity. There was an article in Modern Railways a few months ago discussing this issue as it affects the WCML north of Preston and how maybe the railway is waking up to the problem. Strange really, as it seems blindingly obvious.

It's not something the railway hasn't been aware of for a while. However, the higher the speed for the diverging route the longer the turnout must be, and therefore that affects things like land take, signal positions, and standage. Making the case for higher-speed pointwork usually requires either a useful opportunity (i.e. a complete remodelling), lots of fast passenger trains, or lots of freight trains being looped.
At Pilning, you have the former station platforms, deep cuttings, steep gradients and proximity to the tunnel (a long signal section) to contend with. Having, say, 40mph turnouts while maintaining 775m standage in both directions may well cost an absolute fortune in this particular location.

 

[Annetts key]

Apologies, Pilning. 20mph Entry and Exit doesn't help with the steep grade as well.

The up loop does have an entry speed of 20MPH, but this increases to 35MPH at the signal that controls the exit from the loop. I have no idea why the loop itself has the same speed.

The down loop, has an entry and exit speed of 40MPH, with the whole loop having the same speed throughout.

The main lines at Pilning are 90MPH (normal direction only) in comparison.

Having seen multiple heavy freight trains leaving the up loop, they do indeed struggle to build up speed as they climb the hill towards Patchway.

== Doublepost prevention - post automatically merged: 8 Sep 2025 ==

It's not something the railway hasn't been aware of for a while. However, the higher the speed for the diverging route the longer the turnout must be, and therefore that affects things like land take, signal positions, and standage. Making the case for higher-speed pointwork usually requires either a useful opportunity (i.e. a complete remodelling), lots of fast passenger trains, or lots of freight trains being looped.
At Pilning, you have the former station platforms, deep cuttings, steep gradients and proximity to the tunnel (a long signal section) to contend with. Having, say, 40mph turnouts while maintaining 775m standage in both directions may well cost an absolute fortune in this particular location.

The entry points for the up loop at the west (Wales) side are in a cutting just after Ableton Lane Tunnel (the tunnel portal being at 10m51ch). The Severn Tunnel is a bit further along the line. The up platform is still open for passenger use. The exit points are right before the up platform. The location of the exit signal for the up loop is at 9m56ch. The platform starts at 9m43ch. Note that the railway is on an embankment where the exit points are located.

The platform for the down line is irrelevant because it's parallel with the loop, the loop going round the platform and starting before the platform and ending after the platform.

What is relevant, is that the entry points for the down loop were originally a crossover from the down line to the spur line/down loop. The spur line having stop blocks further towards Patchway. Although this line did stop short of the road bridge (Shaymoor Lane). Hence although the line is on an embankment at this point, it's not a problem.

At the exit for the down loop, again, although in a cutting at Ableton Lane (but far from the tunnel) there is a spur line beyond the crossover that takes you to back to the down line.

So, that may explain why there is less of an issue with the down loop. It is likely that if there was money available, the up loop could be improved at the expense of the standage.

As it currently is, the down loop is 1283m (4209ft). These figures from the sectional appendix. No length is given for the up loop.

 

[zwk500]

Thanks for the details @Annetts key