Devon & Filton banks - could electrification on uphill sections be possible?

[jimm]

I think Temple Meads is the big problem here, needing a major remodelling and re-signalling which nobody seems to have even thought about very much yet. Until this is done there is little point in electrifying either route, except perhaps for an incremental extension to Bath. I would even hazard a guess that this makes the Bristol routes are more difficult than Cardiff-Swansea.

No, naturally Network Rail has done no work whatever on planning for remodelling and resignalling around Bristol... and they are just quadrupling Filton bank without working out how to connect up the new track...

 

[edwin_m]

No, naturally Network Rail has done no work whatever on planning for remodelling and resignalling around Bristol... and they are just quadrupling Filton bank without working out how to connect up the new track...

The first part of the line from Dr Days junction was never reduced from quadruple so that part doesn't really require any thought, as demonstrated from the fact that it will be done before the re-signalling.

 

[edwin_m]

There's an approved scheme for Temple Meads and data testing is underway. No idea of dates for spades in the ground though. The whole resignalling programme was rejigged to prioritise the South Wales line.

Thanks for the information. There seems to have been nothing in the press about this, unlike things like the Derby remodelling which have been known about (if not in detail) for several years.

 

[HowardGWR]

The first part of the line from Dr Days junction was never reduced from quadruple so that part doesn't really require any thought, as demonstrated from the fact that it will be done before the re-signalling.

Oh yes it was (and is). I think you will find jimm was being sarcastic.

 

[edwin_m]

Oh yes it was (and is). I think you will find jimm was being sarcastic.

Quadruple track still exists north of Dr Days, as shown in the view below (looking east). It is too short to have any signals but it means that the quadrupling doesn't affect the signalled routes over the Temple Meads station throat.
https://binged.it/2xxVjpZ

 

[jimm]

Quadruple track still exists north of Dr Days, as shown in the view below (looking east). It is too short to have any signals but it means that the quadrupling doesn't affect the signalled routes over the Temple Meads station throat.
https://binged.it/2xxVjpZ

Yes, and...?

Nothing to do with the point I was making - with just a bit of light sarcasm - that people at Network Rail have been working on Bristol remodelling and resignalling proposals for some years now, as opposed to what you said.

I think Temple Meads is the big problem here, needing a major remodelling and re-signalling which nobody seems to have even thought about very much yet.

And the resignalling and remodelling isn't just about the station and adjacent junctions.

Not that any of this is anything to do with the Devon banks anyway.

 

[edwin_m]

Nothing to do with the point I was making

That's why it was posted below a quote from someone else.

that people at Network Rail have been working on Bristol remodelling and resignalling proposals for some years now, as opposed to what you said.

Yes, I have already noted that point in a previous post - I chose to achnowledge another poster who made it rather more politely.

And the resignalling and remodelling isn't just about the station and adjacent junctions.

But that's the difficult and expensive bit and the bit that leads to removal of the power box, unlocking extra platforms in the Digby Wyatt shed.

 

[PHILIPE]

The thread seems to be discussing Filton bank rather than it's Devon Banks title.

 

[jimm]

That's why it was posted below a quote from someone else.

Yes, I have already noted that point in a previous post - I chose to achnowledge another poster who made it rather more politely.

But that's the difficult and expensive bit and the bit that leads to removal of the power box, unlocking extra platforms in the Digby Wyatt shed.

You weren't being very polite about people at Network Rail who have been working very hard on the Bristol area scheme for some time, were you?

Indeed, utterly dismissive of their efforts on the basis of this remark, which was what I pointed out in the first place:

I think Temple Meads is the big problem here, needing a major remodelling and re-signalling which nobody seems to have even thought about very much yet.

Here's an article from Rail Engineer from last year about the amount of thought that was going into the Bristol area.

https://www.railengineer.uk/2016/10/26/bristol-area-signalling-renewals/

The delivery dates cited obviously pre-date the Hendy Review, but the latest CP5 delivery plan (from June this year) says Bristol East Junction renewal and remodelling is targeted for completion in December 2019 and

Bristol Area Signalling Renewal is a core interface to this project, particularly the phase to re-signal Bristol Temple Meads station which needs to precede this project.

so someone at Network Rail is clearly still thinking about it.

 

[HowardGWR]

Quadruple track still exists north of Dr Days, as shown in the view below (looking east). It is too short to have any signals but it means that the quadrupling doesn't affect the signalled routes over the Temple Meads station throat.
https://binged.it/2xxVjpZ

Yes, for a few yards. I see your point now but I think we already have a Filton bank thread and I think this discussion would be better carried there. The resignalling of this area has been planned for some years now, as jimm points out..

 

[Brunel 1954]

I am sure I recall there was a study done about 70 years ago or more that suggested rather than conventional wisdom of starting in London and electrifying to Penzance, actually start in the South West of England and work forwards exactly because of the Devon Banks.

I love the idea but politicians will not I fear.

Details of a GWR proposed electrification scheme are contained in a book called "The Last Station" by Christian Barham.

 

[squizzler]

I can see problems with weight distribution, perhaps the non electric ones needing a ballast weight instead of an engine, or was the suspension setup going to be tweaked on the originally planned electric sets to cope with a lighter vehicle.

Would I be correct in thinking that modern trains use air secondary suspension, and the train will automatically compensate for different weights by letting some air out the airbags?

 

[edwin_m]

Would I be correct in thinking that modern trains use air secondary suspension, and the train will automatically compensate for different weights by letting some air out the airbags?

Up to a point. I think the air bags are all connected to each other so they won't compensate for a difference in weight distribution. And leaving out something as heavy as a diesel engine with fuel tanks probably takes the vehicle beyond the limit of the primary suspension, which is still done by springs. It may be though that Hitachi have some way of tweaking the suspension to work equally well without having to add ballast.

 

[QueensCurve]

Incredibly for someone with a degree in history he seems absolutely oblivious the the fact that history is repeating itself.

Those who didn't study history, and Mr Grayling, are doomed to repeat it. Those who did study history are doomed to watch other repeating it.

Mr Grayling, who exercises extreme austerity with the truth, has informed us that the wonderful new technology represented by bi-modes obviates the need for the ugly wires in sensitive areas. Bath and Windermere are therefore condemned to suffer diesel pollution for the foreseeable future.

 

[Cliveblackpool]

Hope these trains live up to DfT expectations? With huge advances with battery technology, some banks of batteries in lieu of a couple of generators may have given that extra power for the banks, and shortly after capturing the regeneration when braking, may also improved efficiency, and the environment.

 

[The_Engineer]

Have I just heard right, that the DfT and/or Network Rail are now seriously considering electrifying the big Devon banks?? It implies concern over timings (i.e. performance) being too poor.... Second hand information I am afraid, but I believe the article is a short paragraph in this month's Railway Magazine??

Does anyone know for sure whether this is true, or just a journalistic fancy?

 

[edwin_m]

Have I just heard right, that the DfT and/or Network Rail are now seriously considering electrifying the big Devon banks?? It implies concern over timings (i.e. performance) being too poor.... Second hand information I am afraid, but I believe the article is a short paragraph in this month's Railway Magazine??

Does anyone know for sure whether this is true, or just a journalistic fancy?

Would it be the April issue by any chance?

The GWR considered this back in the 30s but in a modern context the 800s should have enough powered axles to overcome the adhesion issues that HSTs occasionally have, and my impression is that the sections concerned are so curved that even an electric train with unlimited power wouldn't make much difference to timings.

 

[The_Engineer]

Would it be the April issue by any chance?

Yes, it was! I'm trying to borrow it to see for myself.......

 

[delticdave]

Yes, it was! I'm trying to borrow it to see for myself.......

This concept is mentioned in September 2018 Modern Railways too.
No details of course, probably just the uphill sections of the various inclines, with just one feeder point at Totnes & links between the up & down roads at the summits?

DC

 

[Taunton]

The GWR considered this back in the 30s.

The GWR scheme was for the through route from Taunton (of course) to Penzance. THe expense of the assisting locomotives was part of it, but also the cost of hauling the loco coal all the way from South Wales. It was never clear though in the report (done by mainstream electrical engineering consultants Merz & McLellan) how much this would be offset by haulage of coal to the electrical generating stations.

Grierson, the GWR civil engineer, had previously been asked to prepare detailed designs for diversionary routes to avoid the extremely steep Devon banks, but Churchward, who had a long-running high level feud with Grierson, proposed to the GWR board that he could design locomotives to handle the gradients at much lesser capital expenditure.

 

[coppercapped]

The GWR scheme was for the through route from Taunton (of course) to Penzance. THe expense of the assisting locomotives was part of it, but also the cost of hauling the loco coal all the way from South Wales. It was never clear though in the report (done by mainstream electrical engineering consultants Merz & McLellan) how much this would be offset by haulage of coal to the electrical generating stations.

Grierson, the GWR civil engineer, had previously been asked to prepare detailed designs for diversionary routes to avoid the extremely steep Devon banks, but Churchward, who had a long-running high level feud with Grierson, proposed to the GWR board that he could design locomotives to handle the gradients at much lesser capital expenditure.

All true, but these days, also even with the power-limited Class 80X, it is not the hills which are the limiting factor, but the curves.

 

[Pigeon]

I've never really understood why people say this. The atmospheric system worked (when it worked at all) by pumping the air out of the pipe ahead of the train, so its tractive effort was theoretically limited to one atmosphere multiplied by the cross-section of the pipe. In practice it would have been considerably less due to imperfect vacuum and friction.

Thank goodness someone else has noticed this, I thought I was the only one. That the atmospheric system "makes light of gradients" is true only in that wheelslip no longer comes into it. But limitations on tractive effort from locomotives can be resolved by using bigger or more locomotives, essentially without limit. The atmospheric system, on the other hand, imposes a hard limit on tractive effort which in turn means that there is a certain maximum weight of train that it can haul up a given gradient. They were lucky that the bit they did install proved troublesome enough to put them off, because if they had installed it over the banks, 22-inch pipe notwithstanding, they would still have had to rip it all out again or else be forever limited to 1840s train weights.

Also, the gradients were not the consequence of the route being selected with atmospheric traction in mind; the atmospheric suggestion came in a few months after the route had been decided. It wasn't a case of "we can ignore gradients because our technology will make them irrelevant", it was "we're stuck with these gradients, but maybe this technology will make them less of a problem than we thought they would be".

It is not possible to get from Exeter to Plymouth without heavy gradients by any route; I suspect Brunel's aim in choosing the route he did was to make as much of it as possible trouble-free, and concentrate the difficulties in one circumscribed area, so that the special measures needed to deal with them did not affect the ease of operation over most of the route. Much like the London-Bristol route where he concentrated the gradient into the Box stretch and left the rest of it nearly flat.

 

[snowball]

There's an approved scheme for Temple Meads and data testing is underway. No idea of dates for spades in the ground though. The whole resignalling programme was rejigged to prioritise the South Wales line.

Does that include the remodelling of Bristol East Junction? The article on Filton Bank in the August Modern Railways gave the impression that some key aspects of that were not yet decided.

Edit: oops, I didn't notice I was replying to a year-old post! I just noticed that it was dated "27 Sep" and assumed it meant this year!

 

[thaitransit]

I do wonder weather using a standard gauge version of the Queensland Rail diesel tilt trains would make a huge difference to travel times on this route.

In Queensland it cut over 10 hours off the end to end journey times of the Brisbane to Cairns tilt train. Used take about 34 hours using traditional diesel locomotive hauled stock. Now its about 24 hours end to end using the tilt train.

The narrow guage Queensland tilt trains can get up 165kph in service but most of the route doesn't allow that speed. The trains themselves are very comfortable with a 2 + 1 first class seating that converts into a full lay flat bed. The economy is 2 + 2 seating that has good recline and reasonable legroom.

Something similar for Cornwall services could make a huge difference to travel times and onboard comfort. Especially if it operated as reservation required with booked seat numbers only on all services.

 

[MarkyT]

I do wonder weather using a standard gauge version of the Queensland Rail diesel tilt trains would make a huge difference to travel times on this route.

In Queensland it cut over 10 hours off the end to end journey times of the Brisbane to Cairns tilt train. Used take about 34 hours using traditional diesel locomotive hauled stock. Now its about 24 hours end to end using the tilt train.

The narrow guage Queensland tilt trains can get up 165kph in service but most of the route doesn't allow that speed. The trains themselves are very comfortable with a 2 + 1 first class seating that converts into a full lay flat bed. The economy is 2 + 2 seating that has good recline and reasonable legroom.

Something similar for Cornwall services could make a huge difference to travel times and onboard comfort. Especially if it operated as reservation required with booked seat numbers only on all services.

The gains from tilt in Cornwall would not be so great with the frequent stops made by long distance trains, which once this far west and with no major city beyond Plymouth to dominate demand, become the backbone of the local service on the main line through the peninsula, so it's unlikely many or indeed any of the stops will be removed. Tilting equipment and the heavier bogies it needs can add significantly to the weight of each car which is reflected in acceleration performance, important with so many stops en route. With enhanced permissible speeds for tilting stock only in carefully selected places, tilt fitted UK Voyager diesel trains (class 221) between Reading and Birmingham could not beat the non-tilting variant of the same design (class 220) with the typical stopping patterns on that route when introduced in the early 2000s . This was because of their additional weight at ca 10,000kg per car with their heavier outside frame bogies and tilt equipment. While in certain very limited short sections they could achieve marginally higher speeds, this was more than offset elsewhere as they took longer to get up to maximum speed. Once runs north of Birmingham and Manchester on the WCML to Glasgow (with much longer non-stop segments where tilt gave a benefit) were removed from Voyager operator Cross Country Trains' (XC) portfolio, the nearly new tilt capability on the portion of the 221 fleet they retained was first disabled then removed, but those formerly fitted still all have to drag around those extra 10 tonnes per car from the heavier bogies. The 221s on Virgin West Coast retained the tilt feature for fast running on the WCML, which is required to keep up with the pendolinos on the route. Tilt is hard on rail and wheel-treads as track forces and wear increase significantly with the speed increase possible. Hence there are higher costs in rail replacement and wheel turning. Germany largely abandoned tilting on its regional express services some years ago after an enthusiastic start. I believe additional costs of track and rolling stock maintenance were factors. A fair number of narrow gauge limited express services in Japan use the Hitachi tilt system to gain speed on more sinuous sections, usually through hilly areas. The QR trains use Hitachi technology to tilt although the vehicles themselves were built in Australia. Japanese tilt, apparently uniquely suited to narrow gauge use, is simpler and lighter than European implementations, but delivers a smaller angle of inclination. While tilt no doubt had an impact I'm sure that the majority of the performance improvement from introducing the new trains on the QR system was simply from their higher power to weight ratio compared to former loco hauled consists.

http://www.hitachi-rail.com/products/rolling_stock/tilting/feature05.html

 

[thaitransit]

This probably also explains why Queensland is the place in Australia to successfully use tilt trains in regular service. Plus they still do to this day.

In NSW with the NSW trainlink regional train replacement program it has been wondered will they adopt tilt train technology eventhough it was a failure 30 years ago in NSW using European technology. This answer appears unknown at this stage.

 

[MarkyT]

This probably also explains why Queensland is the place in Australia to successfully use tilt trains in regular service. Plus they still do to this day.

In NSW with the NSW trainlink regional train replacement program it has been wondered will they adopt tilt train technology eventhough it was a failure 30 years ago in NSW using European technology. This answer appears unknown at this stage.

Ah yes, NSW has to replace the XPT soon don't they. I don't see why a Japanese tilt system would be incompatible with standard gauge. In fact, one of the latest Shinkansen designs, the N700 series, incorporates tilt to raise speeds on the earliest parts of the network which still contain 2500m curves. It only goes to 1 degree of inclination though and I don't know whether the mechanism was derived from the narrow gauge application. 700s had an active but non tilting suspension system in earlier variants so it may be a development of this similar to Bombardier's FLEXX mechatronic active designs that can incorporate a small amount of tilt and body roll compensation as well as steer the axles in the bogie for a better ride and and less wear.
https://www.bombardier.com/content/...rdier-Transportation-FLEXX_Tronic_WAKO-EN.pdf

 

[thaitransit]

I hope NSW Trainlink does go for diesel tilt trains as it has potential to cut traveling times and maybe even offer a smoother ride too.

The current XPT stock is 37 years old and DMUs are about 25 to 30 years old. The failure rates are increasing on all of this rolling stock. The rolling stock utilization is absolutely hammering the XPTs as they can travel in a typical rolling stock roster from Sydney to Melbourne, Melbourne to Sydney, Sydney to Grafton, Grafton to Sydney before seeing the workshops again. In that time clocking up over 3000km alot of it on rough track especially between Albury and Seymour where it has been so rough that couplers have been broken cargo trains! Even on the passenger train they would warn passengers against walking around the train in this section.

The rough track is caused by 200km of track that is constantly subject to huge mudholes and dips after any significant wet weather .