Midland Mainline Tilt - Good or Bad idea

[Prestige15]

Just a thought. Should the Midland Mainline follow the West coast mainline by upgrading the whole line to tilt capability be a good idea or a bad idea?

 

[Roast Veg]

Unfortunately it just isn't enough of a benefit. The infrastructure changes would only allow for a few sections of higher speed running, but the real pinch points around the cities and major junctions would remain unchanged.

 

[HH]

Is the OP under the misapprehension that the MML is similar to the WCML?

 

[LNW-GW Joint]

Tilt seems to have had its day, despite working well on the WCML.
Part of the business case at the time was it was the only way to get 125 (even 140!) mph out of the line, and to increase route capacity to 9-11tph.
The MML doesn't have the same capacity issues, and NR has been able to get some 125mph running without tilt, despite the curvy route.
There's also the issue of Thameslink running slower non-tilt stock on the fast lines to Bedford.

The direction of travel on the WCML is to dispense with tilt after HS2 comes in, as the classic-compatible stock will not (it seems) be capable of tilting.
There will also be a sizeable fleet of Pendolinos with nothing to do after 2026, cascaded from Birmingham/Manchester/Liverpool/Glasgow etc services.
There will also be 20 tilting Voyagers available, potentially 44 if XC give theirs up.
TASS is a mature technology, and it could be deployed elsewhere if NR and the TOCs have the will.
But I don't think they have.

 

[HSTEd]

There are few places where tilt would make a significant difference however.
One that might be would be to deploy TASS in Cornwall (which would be useful with Voyagers only) or somewhere in Scotland.

BUt most other places have hard limits on linespeed that are not dependent on curvature.

 

[jopsuk]

Tilt is only feasible where the reason for the linespeed limit is comfort, not where the speed round curves is more to do with safe operation. Tilt has little impact on the centre of gravity.

 

[edwin_m]

Tilt is only feasible where the reason for the linespeed limit is comfort, not where the speed round curves is more to do with safe operation. Tilt has little impact on the centre of gravity.

The speed round a curve at which passenger comfort becomes unacceptable is always much less than the speed at which there is a risk of overturning. Though there could be other reasons to limit speed round a curve, such as track condition.

 

[AlexNL]

TASS is a mature technology, and it could be deployed elsewhere if NR and the TOCs have the will.
But I don't think they have.

I would expect ETCS to take over that role going forward.

 

[HSTEd]

TASS is ETCS though

 

[najaB]

TASS is ETCS though

That is totally incorrect. TASS has no connection to signaling.

 

[SpacePhoenix]

What's the "lower speed" threshold below which tilt capability either doesn't work or is a waste of time and money?

 

[edwin_m]

That is totally incorrect. TASS has no connection to signaling.

Although TASS balises are "dumb" with no connection to the signalling, they are ETCS balises and TASS is defined in standards as a UK-specific extension to the basic ETCS spec. So it should be possible to obtain ETCS equipment which also incorporates the TASS functionality.

 

[FordFocus]

TASS is ETCS though

No boss. TASS as far as I'm aware just informs the Pendolino (or Voyager) on where to tilt and possibly the max speed.

Only form of signalling protection is TPWS and AWS.

 

[najaB]

Although TASS balises are "dumb" with no connection to the signalling, they are ETCS balises and TASS is defined in standards as a UK-specific extension to the basic ETCS spec. So it should be possible to obtain ETCS equipment which also incorporates the TASS functionality.

I don't disagree with that conclusion but saying that TASS is ECTS is the same as "Cows have four legs, dogs have four legs therefore dogs are cows."

 

[Jonny]

There are few places where tilt would make a significant difference however.
One that might be would be to deploy TASS in Cornwall (which would be useful with Voyagers only) or somewhere in Scotland.

BUt most other places have hard limits on linespeed that are not dependent on curvature.

Would that need Class 221s with the tilt (re-)enabled though?

 

[CosherB]

Just a thought. Should the Midland Mainline follow the West coast mainline by upgrading the whole line to tilt capability be a good idea or a bad idea?

Bad idea. End of.

 

[43096]

Bad idea. End of.

Says user with a Pendolino as an avatar!!!!!

I suspect that once HS2 opens then tilt will be dead in this country, so that 221s and 390s will ultimately be replaced by non-tilting stock once they are life expired.

IMHO that can only be a good thing given the body profile needed for tilt in the already restricted UK loading gauge. Having spent 4hrs yesterday feeling bloody uncomfortable sat on a Voyager the tilt profile is very definitely an issue.

 

[RichmondCommu]

Says user with a Pendolino as an avatar!!!!!

I think the forum member was referring to tilt on the MML and not tilt in general.

 

[RichmondCommu]

Bad idea. End of.

Hmm. I would be interested to know how much time could be saved between Sheffield and London if tilt was introduced.

 

[edwin_m]

From https://en.wikipedia.org/wiki/Advanced_Passenger_Train

It [APT-E] then set the route record from Leicester to London St. Pancras in 58 minutes 30 seconds on 30 October 1975, at an average speed of just over 101 miles per hour (163 km/h) through this twisty route.[

Today the 222 on the fast Sheffield does London to Leicester in 62min. That's a public time inclusive of timing margins, so if a 222 was to do the run under test conditions as APT-E did, it would achieve within a minute or two of the same time. The route north of Leicester is generally better aligned so there would be proportionately less benefit from tilt.

 

[Rob F]

From https://en.wikipedia.org/wiki/Advanced_Passenger_Train



Today the 222 on the fast Sheffield does London to Leicester in 62min. That's a public time inclusive of timing margins, so if a 222 was to do the run under test conditions as APT-E did, it would achieve within a minute or two of the same time. The route north of Leicester is generally better aligned so there would be proportionately less benefit from tilt.

Yes, but that time is, in the main, due to infrastructure improvements since APT's time. If a run was allowed today by a tilting train that was allowed to exceed the current line speed limits, as APT did, I wonder what the time would be?

ROB

 

[Mikey C]

An interesting question is how much time saving would make tilting trains on such a journey (Leicester to London) worthwhile, bearing in mind the drawbacks (complication, narrower profile etc)?

 

[Senex]

From https://en.wikipedia.org/wiki/Advanced_Passenger_Train



Today the 222 on the fast Sheffield does London to Leicester in 62min. That's a public time inclusive of timing margins, so if a 222 was to do the run under test conditions as APT-E did, it would achieve within a minute or two of the same time. The route north of Leicester is generally better aligned so there would be proportionately less benefit from tilt.

Though there have been very significant changes to the speed-profile of the line since that APT run. (Slightly OT: does anyone else remember the kilometre markers that were put in between London and Leicester for those APT tests, with many of them lingering on in position for years afterwards?)

 

[HH]

An interesting question is how much time saving would make tilting trains on such a journey (Leicester to London) worthwhile, bearing in mind the drawbacks (complication, narrower profile etc)?

Alliance Rail were claiming something like a 10 minute improvement Edinburgh-London, over the IEP timings, in their Open Access application IIRC. But that saving also encompassed making fewer stops and everything making way for them.

Their application also said they'd put aside £50m for NR to make the required improvements. NR thought it would cost a lot more than that.

Unless you know a lot more about the geography of the route and the current sectional running times, then I'd take that as my starter, so you might save 5 minutes if you were lucky at a capital cost in the hundreds of million pounds, once you factor in the cost of rolling stock. Running costs would be greater too. It's pie in the sky.

 

[Jack Hay]

Loss of tilt on the WCML post HS2 is a pretty bad idea IMO. Has anyone calculated how much the journey time will extend between Crewe and Glasgow/Edinburgh, without it?

 

[The Planner]

No one has said that tilt would be removed, and I very much doubt it will.

 

[Mikey C]

Personally, I'd be happy if my journey to Manchester took say 10 minutes longer with conventional trains, if it meant larger windows and a less cramped interior.

 

[Bald Rick]

Yes, but that time is, in the main, due to infrastructure improvements since APT's time. If a run was allowed today by a tilting train that was allowed to exceed the current line speed limits, as APT did, I wonder what the time would be?

ROB

Yes, but... Those infrastructure improvements have raised the line speed to 125mph in many places, and only drops below 100mph at three places in the approx 90miles between Cricklewood and Wigston; therefore the benefit of tilt is reduced.

Many of the restrictions are more about the signalling and tunnels than curvature. But even if they were all about curvature, and full tilt was enabled, I'd be surprised if you saved more than 2 minutes south of Leicester with the existing trains on a non stop run, and for the trains that stop at the Wellingborough etc the benefit would be basically negligible.

 

[JamesT]

Loss of tilt on the WCML post HS2 is a pretty bad idea IMO. Has anyone calculated how much the journey time will extend between Crewe and Glasgow/Edinburgh, without it?

The worst case is after Phase 1 where you have the longest stretch of WCML running by classic compatibles. http://stophs2.org/news/3265-hs2-trains-slow-option-wcml quotes an increase of 13 minutes for Glasgow to Lichfield on 110mph non tilting stock compared to 125mph tilt.

 

[CosherB]

I think the forum member was referring to tilt on the MML and not tilt in general.

Thank you for making that clarification, you're spot on. At least someone understands the context of the comment!