Salisbury - Exeter punctuality improvements?

[Kite159]

Are those sections in the right place to help make the service reliable? Do down trains typically get held waiting for an up at Tisbury?

Yep.

 

[Zomboid]

Yep.

In which case it's Tisbury platform 2 that's needed

 

[PTR 444]

The big problem with rebuilding the bridge is that the next junction north on the M5 is miles away at Cullompton - the old A38 just wouldn't be able to cope if you closed the motorway entirely. It would have to be done by by alternately closing each carriageway.

Surely the official diversion route for M5 traffic would be up the A30 to Honiton, then A303 to Ilminster and A358 back to M5 Junction 25?

Only Exeter - Cullompton traffic would then need to use the old A38, as the A377/A396 route can cater for the Exeter - Tiverton/North Devon flow.

 

[Harpo]

I would start by finding out the facts, the real root causes of delay, and addressing them.

Otherwise spending billions on incredibly expensive upgrades alone without investigation only gives you a shinier railway to run your late trains on.

 

[The Ham]

I would start by finding out the facts, the real root causes of delay, and addressing them.

Otherwise spending billions on incredibly expensive upgrades alone without investigation only gives you a shinier railway to run your late trains on.

Indeed, although there are some areas where other factors come to play. For example the desire to improve service frequency for the Devon Metro would mean that redoubling west of Honiton didn't only give you a "shinier railway" but also give you more services.

Also, arguably, there's an argument that (given the cost to make changes) it's potentially better value to create as long a section of double track as you can before the next big cost comes into play rather than just the minimum to create a loop.

For example, if you've got the fixed costs of a set of signals at each end and the associated trackwork, it's better to build it (say) 5km long than 500m long. As that's likely to reduce the impact of more of the delays yet the cost wouldn't be anywhere near as much as 10 times there amount even though the distance is.

Over the long term one single 5km loop may even be cheaper and provide nearly as many benefits as 2 loops of 500m.

 

[Harpo]

Also, arguably, there's an argument that (given the cost to make changes) it's potentially better value to create as long a section of double track as you can before the next big cost comes into play rather than just the minimum to create a loop.

So long as it doesn’t deliver (like many rationalisations did) inflexible timetabling options. ‘Ossification’ used to be the BS Bingo word for that.

 

[The Ham]

So long as it doesn’t deliver (like many rationalisations did) inflexible timetabling options. ‘Ossification’ used to be the BS Bingo word for that.

Indeed, however I did start my post by agreeing that it had to be evidence lead, which was why I was suggesting that a single longer loop may be better than two shorter ones - although in the context of evidence lead improvements (i.e. it may not be).

 

[Zomboid]

would start by finding out the facts, the real root causes of delay, and addressing them.

Agree, but there's value in resilience enhancements so that when delays do occur they can be mitigated and don't snowball.

In the current timetable it looks like trains are generally scheduled to pass at Pinhoe, Axminster, Sherborne and Tisbury. And Tisbury seems an obvious candidate to cause delays to snowball with the station just off the loop so any delayed up train has to decelerate, stop, do it's station business and accelerate away before a down can do anything. Putting the station on a loop would mean that as soon as the up clears the single line, the down can go Notch 8 and should be delayed less, or might even avoid it entirely.

 

[martin butler]

I think the only way, would be to re double the entire route west of Salisbury and electrify using overhead from Basingstoke and cascade 800'S onto the route, but if we were talking the best use of the route, I would say re open the closed section from Okehampton, to Plymouth and electrify the entire Route from Bristol to Plymouth, and also the northern route, and operate some Plymouth services out via Oakhampton, and return via Dawlish, and bristol that way, theres no resersals, and i don't think times on the routes would be much different

 

[AlastairFraser]

I think the only way, would be to re double the entire route west of Salisbury and electrify using overhead from Basingstoke and cascade 800'S onto the route

Why 800s? I'm not sure they could even be reasonably modified to use 3rd rail.

 

[martin butler]

Why 800s? I'm not sure they could even be reasonably modified to use 3rd rail.

I was thinking, if the line was electrified using OH, services could run from Paddington, via Reading , Basingstoke for local services SWR could use 378's running on 3rd rail, changing over to overhead at Basingstoke to serve Salisbury and all stations, to exeter,

 

[Zomboid]

It's certainly something that could be done with some crayons, but it'd only be the thing to do if the problem statement was to make the Waterloo route the principle way to get to the south west.

A reliable hourly service, with maybe a bit of headroom for peak time extras and GWR diversions is a more reasonable target.

 

[AlastairFraser]

I was thinking, if the line was electrified using OH, services could run from Paddington, via Reading , Basingstoke for local services SWR could use 378's running on 3rd rail, changing over to overhead at Basingstoke to serve Salisbury and all stations, to exeter,

That doesn't make any sense. That would use a chunk of the limited capacity on the Great Western Main Line, to provide a roundabout service to/from London on a slow line to the South West.
Whatever happens re electrification or new stock, the line is only operated logically if it is operated from Waterloo.

It's certainly something that could be done with some crayons, but it'd only be the thing to do if the problem statement was to make the Waterloo route the principle way to get to the south west.

A reliable hourly service, with maybe a bit of headroom for peak time extras and GWR diversions is a more reasonable target.

Certainly!

 

[The Ham]

Something which is worth remembering is that if the line were to see just 2% growth year on year, we'd need double the capacity in 35 years time.

Whilst that's quite a while off, it also highlights that you don't need a lot of growth to see some fairly large longer term passenger numbers.

As such, it's unlikely to be that wasteful to look at improvements to infrastructure as usage is likely to increase.

 

[brad465]

Stations like Templecombe would need a lift etc installed. The current platform stands in the previous down line, with the old up platform now a volunteer garden but out of operational use.

Is the provision of step-free access now a legal requirement in the building/reopening of any new station, and/or adding additional platforms to single-platform stations? I'm guessing so as lift installation seems to be very good at trashing business cases for any of the aforementioned improvements.

If building a ramp up to a road bridge that crosses over the line, or down to a road that passes under, were cheaper than lifts while still meeting any legal requirements, then Templecombe (underpass), Crewkerne (road bridge) and Feniton (level crossing) could all be redoubled without having to install lifts.

 

[The Ham]

Is the provision of step-free access now a legal requirement in the building/reopening of any new station, and/or adding additional platforms to single-platform stations? I'm guessing so as lift installation seems to be very good at trashing business cases for any of the aforementioned improvements.

If building a ramp up to a road bridge that crosses over the line, or down to a road that passes under, were cheaper than lifts while still meeting any legal requirements, then Templecombe (underpass), Crewkerne (road bridge) and Feniton (level crossing) could all be redoubled without having to install lifts.

Part of the issue with ramps is they need to be over 100.1m long for a rise in level of 5m (circa 5m loading gauge, plus circa 1m for the bridge deck less circa 1m for starting at platform level).

That either means the platforms need to be some distance from the bridge and/or there's enough space to double back the ramps.

If course that's counter balanced by the fact that a new bridge (even without lifts) is likely to be £3 million or more.

 

[Zomboid]

But I don't think there's anything that would prohibit both platforms being accessed from separate entrances. Islip is a recent example where there's a stepped footbridge and ramps from the road bridge. No immediately obvious reason why that kind of thing couldn't be applied at places like Templecombe.

 

[The exile]

But I don't think there's anything that would prohibit both platforms being accessed from separate entrances. Islip is a recent example where there's a stepped footbridge and ramps from the road bridge. No immediately obvious reason why that kind of thing couldn't be applied at places like Templecombe.

It then requires the pavement over / under the bridge between the entrances to be wide enough to take additional traffic (not sure if this applies where there is no car park for people to need to return to.

 

[duffield]

I was thinking, if the line was electrified using OH, services could run from Paddington, via Reading , Basingstoke for local services SWR could use 378's running on 3rd rail, changing over to overhead at Basingstoke to serve Salisbury and all stations, to exeter,

As per another post, capacity out of Paddington is a problem, in fact we've had it stated on a Heathrow Express thread that even if HeX was shut down to free up paths to Airport Junction, there really aren't any paths available between there and Reading. Continuing services out of Waterloo really seems the only realistic option. If you're going for 3rd rail out of Waterloo+OHLE later on, something like the now tried and tested Thameslink class 700s might seem a good option, just with different seating better suited to the distance and nature of the route. I'm not convinced that the 378 overground stock would be suitable, with its 75mph top speed, even with different seating.

 

[pompeyfan]

I did say at the start of the thread I wanted sensible easy wins (and also an insight as to why punctuality has declined). I’d really like to avoid crayonista ideas please.

 

[Zomboid]

It then requires the pavement over / under the bridge between the entrances to be wide enough to take additional traffic (not sure if this applies where there is no car park for people to need to return to.

The bridge at Templecombe would need a lot of work too meet that kind of requirement, an accessible footbridge might actually be easier. Though since trains are scheduled to pass at Sherborne anyway it's not as important/ beneficial to put a second platform in there as it would be for Tisbury.

 

[swt_passenger]

I was thinking, if the line was electrified using OH, services could run from Paddington, via Reading , Basingstoke for local services SWR could use 378's running on 3rd rail, changing over to overhead at Basingstoke to serve Salisbury and all stations, to exeter,

Did you mean 387s? 378s are LO, why would they ever be moved?

 

[martin butler]

Did you mean 387s? 378s are LO, why would they ever be moved?

Sorry yea i did mean 387's not the LU units,At some point the existing 159'S will need to be replaced, if the Exeter route was electrified, then a dual voltage unit, would make operational sence as it could still be used on the 3rd rail routes, so making it a class of unit that could work anywhere on the system, electrics have better acceleration, so could reduce section times,

 

[brad465]

I did say at the start of the thread I wanted sensible easy wins (and also an insight as to why punctuality has declined). I’d really like to avoid crayonista ideas please.

There are probably not many, if any, easy wins here, as any improvements to infrastructure purely to improve the resilience of the existing service would have a poor business case in the current climate. There'd have to be a service enhancement and patronage increase to go with them. For example, redoubling most, if not all, of Axminster-Pinhoe could be sold as part of enhancing the service between Exeter and Axminster, which is an existing service aspiration. Sorting out Tisbury, while probably the area with the most potential for improving resilience, may also need a service enhancement attached to make it worthwhile. This could be achieved if doing so allowed 2tph all day between Salisbury and Yeovil, compared to 1tph with a few additional extensions beyond Salisbury currently.

 

[Grecian 1998]

Going back to the original question, as a user on a monthly basis, I don't think it's a single cause - more a mixture of:

- The age of the 159s - they've been great workhorses for the line and very well maintained at Salisbury for most of that time (SWR's changes at the franchise handover in 2017 didn't seem to be for the best), but they're over 30 years old and won't last forever.

- Dwell times - there's no planned dwells of more than one minute between Salisbury and Exeter Central in either direction, so if something causes an extended dwell, there doesn't seem to be any contingency time built into the timetable. The up Waterloo is heavily reliant on the down Exeter being on time at Pinhoe and Tisbury loop if it isn't to lose time.

As has been mentioned above, a short formed train of 3 coaches is particularly susceptible to extended dwells due to overcrowding.

- Aging infrastructure / vegetation issues - in recent times there's been significant permanent speed restrictions between Tisbury and Gillingham (fragile embankment) plus the problems at Crewkerne and Honiton Tunnels.

The sheer lack of resilience in the timetable - if and when something goes wrong during the day, it's very hard with the existing infrastructure to get the timetable back on track before the end of service. It's documented by the Salisbury - Exeter rail users group that trains are usually on time at 0800 but rarely on time at 1700.

Additionally, the infrastructure isn't set up to get failed trains out of the way. I was on an eastbound service which was cancelled at Axminster last October due to one of the two 159s forming the service being deemed to have failed. That train then limped empty to Yeovil Junction at 20mph. The following service had to plod a long way behind it due to the signalling sections, arriving at Yeovil Junction around 50 minutes late.

Network Rail's route study in 2020 acknowledged that the current infrastructure cannot deliver a reliable hourly service. Unfortunately, as has been said above, there are few quick wins and little prospect of funding for enhanced capacity.

 

[JamesRowden]

What about getting some new bi mode stock with supercapactors to regenerate energy when deccelerating, and providing a boost when accelerating to provide AC EMU levels of acceleration performance, including when on the third rail between Basingstoke and Waterloo?

The greater acceleration could be used to provide greater padding to the timetable through the single track sections, therefore making the timetable more reliable and able to recover faster.

Perhaps the idea for partial electrification and battery trains is a variant of this idea.

Line speed upgrades or making some station stops 2 hourly would provide resilience in a similar way.

 

[devon_belle]

Line speed upgrades or making some station stops 2 hourly would provide resilience in a similar way.

The line has some pretty tight curves. It was mostly* blanket 85 mph throughout, though few trains could achieve that except down the steepest banks. I suspect that there would have been more speed restrictions had the line kept its double track, and that if reintroduced it may force some reductions in speed. I think modern stock with faster acceleration will provide much more of a benefit to the timetable than higher speed limits, particularly as almost every service stops everywhere.

On that point, I imagine that if there were benefits of skip-stopping some stations they would still be doing it, however I think this ended when Cranbrook was opened (?). The best candidates would probably be Pinhoe, Feniton, and Whimple, but this would not be acceptable before the Devon Metro scheme achieves regular GWR services to Axminster/Honiton. Even then, the likes of Pinhoe especially deserves more than 1 tph, which is why it would be good if a crossover could be put in to allow GWR trains to terminate there rather than St James Park (or the siding at Exmouth Junction). As Pinhoe serves a significant chunk of East Exeter I don't think it should lose its London service at this stage.

* There was a 70 mph limit between Sidmouth Junction (Feniton) and Whimple, and a 60 mph limit on the sharpest Up curve just before Seaton Junction. There may have been one or two more, but I can't remember off the top of my head.

 

[Zomboid]

Whimple and Feniton are already served by alternate trains for most of the day.

From 10 minutes with a spreadsheet, it doesn't look completely unreasonable to increase the service between Salisbury and Yeovil to 2tph. If you just add 30 minutes to an existing train, the new ones would meet at Tisbury and Sherborne, whilst they would be at Gillingham within 4-5 minutes of the existing trains. So a second platform at Tisbury and perhaps a bit of a longer dwell there and at Gillingham might make something workably resilient. That's obviously very simplistic, and as the trains would most likely be extensions of the Salisbury terminators it probably wouldn't be an even 30 minute gap, but I don't think we'd be talking megabucks of infrastructure to allow it - and it might justify a second platform at Tisbury.

Though whether there's any need for such a train is another matter.

 

[brad465]

Line speed upgrades or making some station stops 2 hourly would provide resilience in a similar way.

My idea for Axminster-Exeter is to redouble it all (or at least enough to allow the following proposal) and have a 2tph GWR stopping service call all stations, with the hourly SWR service running fast from Exeter to Honiton, possibly also serving Cranbrook if airport links were sorted out. Every station in this section would have an enhanced service frequency, while the SWR service is sped up through fewer calls and allows for more turnaround time at the Exeter end in the event of disruption.

 

[Brubulus]

My idea for Axminster-Exeter is to redouble it all (or at least enough to allow the following proposal) and have a 2tph GWR stopping service call all stations, with the hourly SWR service running fast from Exeter to Honiton, possibly also serving Cranbrook if airport links were sorted out. Every station in this section would have an enhanced service frequency, while the SWR service is sped up through fewer calls and allows for more turnaround time at the Exeter end in the event of disruption.

There's no point in running a fast service to Exeter, the demand to Exeter from beyond Honiton is pretty small. I'd support running the Okehampton and Barnstaple services through Exeter, so 1tph Okehampton to Honiton and 1tph Barnstaple to London.