Class 397 125mph?

[Watershed]

I suppose that potentially if they sign off 110+ limits without tilt north of Preston AND don't tighten the schedules then you could have such a scenario but I don't see that happening, I'm sure they would tighten up the timetable as well to take benefit

It would certainly give better resilience to the timetable and allow for more generous dwell times. I don't think overall journey times would change.

 

[class26]

It's not the train that can't do 125- it's that the speed limit for non-tilting stock is 110. Apparently the plans to increase the speed limits for non-tilting stock have been ditched.

I do wonder though once HS2 is completed if there won't be improvements in the speed north of Preston.

April`s Modern Railways (P15) reports that funding has been awarded to examine options to enhance the WCML in order to accelerate services going onto Scotland. Presently , with HS2 the London - Glasgow time will be 3 hrs 40 mins, the aim being to get this down to as close as possible to 3 hours so this does suggest speeds in excess of 125 mph in parts between Preston and Glasgow if c.40 minutes is to be saved.

 

[bengley]

Though with the curve through Wigan and slow speed through Preston, you'll be lucky to sustain much better between the two than today- especially with the climb out of Wigan holding back top-end acceleration a little.

You could easily get to and maintain 125 in a 397 in either direction between Wigan and Preston. You'd be doing 125 by Coppull after leaving Wigan

 

[Bald Rick]

Gareth Dennis wrote a good piece about this some time ago. Long story short; Class 397 acceleration profile + WCML 125mph testing determined that tilt wasn't required.

As has been said in the other threads about this subject, the acceleration doesn’t give that much time, certainly not enough to offset the lack of tilt. If exceptional curving rules are applied, then the non-tilt speed limit could be raise din some places, but you’d need to hold on to your drinks.

 

[hexagon789]

It would certainly give better resilience to the timetable and allow for more generous dwell times. I don't think overall journey times would change.

Well it's one option anyway, perhaps making the timetable more regular would be better, it's not a perfect clockface on the departure minutes. Sorting that out and making the journey times all regular might be more beneficial.

As has been said in the other threads about this subject, the acceleration doesn’t give that much time, certainly not enough to offset the lack of tilt. If exceptional curving rules are applied, then the non-tilt speed limit could be raise din some places, but you’d need to hold on to your drinks.

The French and Spanish seem to have no problem with that, but the curve transitions can be quite violent at speed

 

[Watershed]

Well it's one option anyway, perhaps making the timetable more regular would be better, it's not a perfect clockface on the departure minutes. Sorting that out and making the journey times all regular might be more beneficial.

That has more to do with freight paths and the like - there's always going to be slight inconsistencies on a line as busy and varied as the WCML.

 

[Bletchleyite]

Well it's one option anyway, perhaps making the timetable more regular would be better, it's not a perfect clockface on the departure minutes. Sorting that out and making the journey times all regular might be more beneficial.


The French and Spanish seem to have no problem with that, but the curve transitions can be quite violent at speed

Germany too, they don't seem to cant the track anywhere near as much as we do so even small curves throw you around all over the place.

 

[Bald Rick]

Germany too, they don't seem to cant the track anywhere near as much as we do so even small curves throw you around all over the place.

They do, but they just allow higher speeds round them.

 

[hexagon789]

That has more to do with freight paths and the like - there's always going to be slight inconsistencies on a line as busy and varied as the WCML.

Does that really affect the timings that much? I mean this is mainly say one hour the train leaves at :09, then it might be two hours later at :12, then three hours later at :10. Does the freight pathing really mean they couldn't be all the same minutes but still at the same hour gaps

Germany too, they don't seem to cant the track anywhere near as much as we do so even small curves throw you around all over the place.

Can't comment on Germany, but does seem to be the norm on the Continent. The one country I don't recall such an effect was Switzerland, but it might just be the geography inhibiting higher speeds anyway

 

[D6130]

Does that really affect the timings that much? I mean this is mainly say one hour the train leaves at :09, then it might be two hours later at :12, then three hours later at :10. Does the freight pathing really mean they couldn't be all the same minutes but still at the same hour gaps


Can't comment on Germany, but does seem to be the norm on the Continent. The one country I don't recall such an effect was Switzerland, but it might just be the geography inhibiting higher speeds anyway

Curves are usually well-canted on main lines - and many secondary lines - in Italy.

 

[hexagon789]

Curves are usually well-canted on main lines - and many secondary lines - in Italy.

It's not so much the degree of cant more permissible curving speeds I think.

(I would expect more cant to reduce the effect not heighten it.)

 

[Hey 3]

This thread begs the question of why TPX didn't procure tilting stock for their Glasgow and Edinburgh services in the first place, given that about 100% of their route is over the WCML.

Fixed that for you there.

 

[Bletchleyite]

Fixed that for you there.

When did the Preston-Chorley/Golborne-Manchester routes become part of the WCML, then?

 

[The Planner]

Does that really affect the timings that much? I mean this is mainly say one hour the train leaves at :09, then it might be two hours later at :12, then three hours later at :10. Does the freight pathing really mean they couldn't be all the same minutes but still at the same hour gaps

Freight are timed by trailing weight, on a gradient that makes a difference quite rapidly the heavier you are.

 

[hexagon789]

Freight are timed by trailing weight, on a gradient that makes a difference quite rapidly the heavier you are.

Other services can manage to be at fixed minutes and are the freight paths that variable? I mean do you have one freight one hour at one weight and one the next hour that's timed for an extra say 200 tonnes or something?

 

[The Planner]

Other services can manage to be at fixed minutes and are the freight paths that variable? I mean do you have one freight one hour at one weight and one the next hour that's timed for an extra say 200 tonnes or something?

Yes, and at places like Shap it makes a difference.

 

[notadriver]

Above 60 mph Pendolinos accelerate just as well as 802s and 397s. The 397s being forced to use the non eps speed profile means uninterrupted 110 mph is limited compared EPS which has long swathes of 125 mph running north of Carlisle.

 

[Hey 3]

When did the Preston-Chorley/Golborne-Manchester routes become part of the WCML, then?

They became part of it since the Northern Hub, as they have electric wires, allowing AWC to divert when nessecary.

 

[Efini92]

It would also apply to the XC Voyagers that use it every couple of hours.

Xc voyagers can’t use EPS as the TASS has been “permanently” isolated.

 

[hexagon789]

Xc voyagers can’t use EPS as the TASS has been “permanently” isolated.

It's a joint HST/EPS 105 though, so XC Voyagers most certainly can (and do) use it.

 

[Efini92]

It's a joint HST/EPS 105 though, so XC Voyagers most certainly can (and do) use it.

They can use HST differentials but not EPS. Just happens to be the same speed in that location.

 

[hexagon789]

They can use HST differentials but not EPS. Just happens to be the same speed in that location.

Yes, but as far as I could tell that is what the post originally was referring to - that XC Voyagers could use the 105 in that location - not a point on wider use of EPS speeds, which of course no XC 221 can use anymore.

 

[Jonny]

Above 60 mph Pendolinos accelerate just as well as 802s and 397s. The 397s being forced to use the non eps speed profile means uninterrupted 110 mph is limited compared EPS which has long swathes of 125 mph running north of Carlisle.

North of Carlisle might be a relatively easy one to make a business case for raising at least the HST differential to(wards) EPS, as North of Carlisle is also an LNER diversion route; even if it doesn't do much for LNER running times it might squeeze a few extra slots in.

 

[edwin_m]

North of Carlisle might be a relatively easy one to make a business case for raising at least the HST differential to(wards) EPS, as North of Carlisle is also an LNER diversion route; even if it doesn't do much for LNER running times it might squeeze a few extra slots in.

I don't think there would be any need to go for HST differentials - just raise the general speeds. Given that the WCML can support Pendolinos at 125mph and locos at 110mph, there's probably nowhere that is sensitive to high axle loads, and if the Pendolinos can stop within the signal spacing then so can anything else that's cleared for 125mph.

 

[Railperf]

I don't think there would be any need to go for HST differentials - just raise the general speeds. Given that the WCML can support Pendolinos at 125mph and locos at 110mph, there's probably nowhere that is sensitive to high axle loads, and if the Pendolinos can stop within the signal spacing then so can anything else that's cleared for 125mph.

You have to remember that when EPS speeds were introduced, no other non-tilt stock needed to run at more than 110mph on the WCML anyway except for the sections that have HST differentials.
THere are clearly places where 110mph on straight track can be increased to 125mph provided the braking capability of the 397's and 80X matches Pendolino braking distances. Then it is all about how much money needs to be spent recanting curves and altering curve transitions to suit non tilt at higher speeds.

I think Gareth Dennis mentioned that key to this was faster freight speeds - requiring powerful electric haulage. You cannot raise cant much higher if freight is trundling through at low speeds. So a holistic approach is needed.

Interestingly the EPS speeds through most of the freight loops is lower - even if the track on the main line through many of them is fairly straight.

The Carstairs to Edinburgh section looks straight enough to allow higher speeds for much of its length. I guess the cost of resignalling is the issue.
And more time would be saved creating a new Carstairs south junction with a flyover/diveunder allowing speeds of 70mph or higher. Not sure traffic levels warrant that, but it would future proof the junction and reduce conflicts in case of delay.

The time saving for EPS over current non EPS limits is several minutes - which incrementally reduced the complete London to Glasgow time.
TPE schedules are currently v similar to Pendolino's even if the Pendolino SRT's are quicker. Looks like increased dwell times for Avanti are what equal the schedules out in the current timetable.
There must be appx 5 to 8 mins time saving if the 397's could be allowed to run at 125mph vice 110mph between Wigan and Carstairs.

 

[LNW-GW Joint]

Reporters like to give the impression that 397s are already passed for 125mph on the WCML which is of course not true.
Another report I just read in Modern Railways (Aug) is that the class 93/Mk4 sets planned by Grand Union between Stirling and Euston will be planned for 125mph.
I suspect the differential EPS speeds for Voyagers will have to go before a new general WCML speed profile can be introduced and signed, initially for Avanti's 80x due in 2023.
And that might only cover south of Preston/Crewe.
It all seems quite opaque at the moment, particularly the amount of track adjustment to achieve 125mph non-tilt without a saw-tooth profile.
The real driver will be HS2 services on the WCML north of Crewe, but that's the best part of a decade away.
Is there any sign the freight TOCs are happy to use electric traction more?

 

[Watershed]

Is there any sign the freight TOCs are happy to use electric traction more?

I'm sure they'll be happy to use electric traction - if enough money is bunged their way.

 

[hexagon789]

Another report I just read in Modern Railways (Aug) is that the class 93/Mk4 sets planned by Grand Union between Stirling and Euston will be planned for 125mph.

Bizarre, their application makes clear a 110mph maximum service speed and the 93s are 110 max anyway.

 

[a_c_skinner]

This must be solely about lateral forces for passengers, tilt doesn't make the train stick to the track better (unlike cant). I think some parts of the network tolerate higher forces than the WCML (?MML and northern ECML). Can I ask how the limits for lateral forces were set? Does anyone know how all this compares with forces deemed tolerable on other public transport? If it is just about drinks sliding then a different table top seems a reasonable solution to explore. I know this has come up again and again and I've asked this before but I've never had a convincing reply. 110 to 125 gives a 30% increase in lateral forces I think. Are there other EPS differentials where it is bigger?

 

[hexagon789]

This must be solely about lateral forces for passengers, tilt doesn't make the train stick to the track better (unlike cant). I think some parts of the network tolerate higher forces than the WCML (?MML and northern ECML). Can I ask how the limits for lateral forces were set? Does anyone know how all this compares with forces deemed tolerable on other public transport? If it is just about drinks sliding then a different table top seems a reasonable solution to explore. I know this has come up again and again and I've asked this before but I've never had a convincing reply. 110 to 125 gives a 30% increase in lateral forces I think. Are there other EPS differentials where it is bigger?

Worth remembering that the APT speeds were generally higher around curves than they are for Pendolinos (and that includes after the tilt modifications from the Mk2 to Mk3 system), so the higher forces are not unheard of on the WCML.

And as you say - they do exist elsewhere on the network on 125mph lines; though it must be the ride is a bit lively on the ECML north of Newcastle.