WCML - Tilt vs Non-Tilt

[Kingfisher200262]

The current conventional wisdom is that in order for a train to operate at high speed (125 mph plus) on the West Coast Main Line, it must be fitted with tilt, to improve the passenger comfort on certain sections where there are many tight(ish) curves.

However, when BR conceived the IC250 project in the late 1980s, Class 93 electric locos and Mk V coaches were proposed, with a maximum speed of 155 mph (250 km/hr). The proposal was that the coaches would be 26 metres long and would not incorporate tilt.

My understanding is that the only reason this project did not proceed was on grounds of cost, not technical viability / feasibility.

Can anyone set out, in simple terms how thinking has shifted on this and why?

Apologies if this topic has been covered before. If so, please feel free to refer me to the thread.

 

[ainsworth74]

My understanding is that the IC250 project would have incorporated extensive work on the WCML in terms of track realignment and increased cant through corners to allow the higher speeds. I guess the plan was similar to the upgrade that happened in the end but much more extensive than even originally planned by Railtrack/Virgin (let alone what we actually got). So really its less a shift in thinking but more an economic move i.e. its cheaper to do some track work and get tilting trains rather than go for a full out rebuild of the WCML like the IC250 project called for.

At least that's how I understand it...

 

[swt_passenger]

As always, it wouldn't have necessarily meant the whole line was going to be improved anyway. Same as today's WCML isn't 125 mph throughout, even for tiliting trains.

Just like when the ECML and GWML are referred to as 125 mph lines, all they really mean is that they have significant sections where 125 mph is possible, but it isn't 100% by any means.

 

[rail-britain]

The IC250 project would have seen an almost complete realignment of the severe curves between Abington (south of Carstairs) and Lancaster
It wouldn't all have been 155mph, and from memory one section would still have been 95mph (but could have been increased to 110mph if a tunnel was constructed)

 

[LE Greys]

I always thought that IC250 was one of many good projects lost in the rush to privatisation, along with the original Crossrail, various types of Networker, and Classes 62 and 65

The power car looked absolutely stunning, the best bits of a Class 91, 125 and Eurostar power cars

Picture from www.therailwaycentre.com

 

[RobShipway]

I always thought that IC250 was one of many good projects lost in the rush to privatisation, along with the original Crossrail, various types of Networker, and Classes 62 and 65

The power car looked absolutely stunning, the best bits of a Class 91, 125 and Eurostar power cars

Picture from www.therailwaycentre.com

Maybe it's me, but I think the lines are similar to what we have in the Pendolino?

 

[j0hn0]

The thing is though that pendos only run at 125 if theyre late

Any slight delay for the pretendolino and it will be late all the way to brum

And so 155mph would probably only been used when trains were late, but could you imagine the stress on trackwork? Wcml is unreliable in its current "upgraded" guise

 

[The Planner]

The thing is though that pendos only run at 125 if theyre late

Am I mis-reading that ?? they run at 125 all the time.

Any slight delay for the pretendolino and it will be late all the way to brum

It cant keep time in its current path as it is a 125mph timed one.

 

[gordonthemoron]

how fast do pendolinos take corners?

 

[The Planner]

Depends on the corner ! some at 125mph, sharper ones like Weedon at 110

 

[gordonthemoron]

really? ICE-Ts take corners rather slowly (and tilt). They only go fast on straight track

 

[WatcherZero]

Our tracks more curvy and less straight so you need to be able to maintain your speed through corners.

 

[j0hn0]

Am I mis-reading that ?? they run at 125 all the time.

Not according to my gps. I commute every day on wcml, if they travel mostly at 125 then they arrive early. If we leave late by say 5_10 mins then we travel at 125 all the way apart from through mk.

Have definitely hit 132mph at one point though

 

[Zoe]

GPS shows ground speed though. This will not be true speed unless you are dead level.

 

[ainsworth74]

Not according to my gps.

No offence to your GPS but I'm going to take the planners word over its read out

 

[Zoe]

Another one that does the rounds is that HSTs only run at 110 mph between Reading and Swindon unless they are late so that fuel can be saved. I don't know how true this is.

 

[asylumxl]

I'm of the believe they are allowed to go 5 percent over the maximum permitted speed, which equals 131.25mph.

So I don't think it's all that impossible that a GPS device would have recorded such a speed. Most civilian GPS is rated at +/- 5m accuracy, so over large distances it's perfectly accurate. Elevation and gradient should not make a difference assuming your software is able to work out speed in 3 dimensions.

 

[Zoe]

Most civilian GPS is rated at +/- 5m accuracy, so over large distances it's perfectly accurate. Elevation and gradient should not make a difference.

Do the GPS devices have elevation data then so they can calculate a true speed? If all they do is just get your position on the Earth's surface and calculate the your speed for just this then it won't be your true speed.

 

[asylumxl]

Do the GPS devices have elevation data then so they can calculate a true speed?

Yes. Even your most basic TomTom has it. There is usually a bar on TomTom systems and pressing it will bring up the sattelite information, including Longitude/Latitude or Coordinates depending on options, elevation and bearings.

Most Survey equipment companies seem to have pages regarding how the system works, but Trimbles is best, it's quite well laid out.

http://www.trimble.com/gps/index.shtml

 

[Zoe]

Yes. Even your most basic TomTom has it. There is usually a bar on TomTom systems and pressing it will bring up the sattelite information, including Longitude/Latitude or Coordinates depending on options, elevation and bearings.

So they include every cutting and the elevation of the railway within that cutting then?

 

[Pumbaa]

I'm of the believe they are allowed to go 5 percent over the maximum permitted speed, which equals 131.25mph.

Nope - the speedo will start having a hissy fit and set off alarms at 126. Driver then has 7 seconds to reduce speed before E Brake application. They can't turn off the safety either - it radios through to WCT control at Edge Hill/Wembley that the action has been taken. Whoever is watching will then confirm they had permission to, ie shunting over failed grids, and if not they can remote monitor the train while contacting the signal box to ask the driver why the hell he's done it.

Of the top of my head from Rugby to London, coming away from Rugby is 125 (all speeds top EPS for 390s) to the tunnels, where it's 115/110, then you have 125 again until away from the motorway, down to 110, then 115 through the last curves, then 125 all the way down to Bletchley, 110 across Bletchley South (will be 125 after upgrades finished), 125 to Leighton, 115 through the tunnels, 125 through Berko (impressive to say the least), 125 all the way to Bushey Viaduct, 115 across that, then 125 to Harrow, then 115 to Wembley Central, then down to 110, 100 and into Euston approaches.

They will run at linespeed, unless a service in front is schedule to make a stop, the drivers will adjust accordingly to minimise braking.

 

[asylumxl]

So they include every cutting and the elevation of the railway within that cutting then?

It works out the elevation from the GPS sattelites so why would it need it? It's not like railways have incredibly large sudden changes either.

 

[Zoe]

Considering the power controllers in trains are notched, how difficult is it to hold the train at line speed? How far below line speed do you let the train get before you apply power again?

 

[Pumbaa]

Not according to my gps. I commute every day on wcml, if they travel mostly at 125 then they arrive early.

All services will arrive early if they travel at full linespeed. There is slack in all timetables to allow for TSRs and possessions etc. Thats how the timetabling works.

 

[Zoe]

It works out the elevation from the GPS sattelites so why would it need it?

As far as I know GPS sattelites do not offer elevation data only your position on the Earth's surface. It would have to be built into the GPS unit.

 

[asylumxl]

In reply to you Pumbaa, I swear I read such a thing on this forum, there was a thread about it a while back. But as we are both aware, railway forums are not always the most reliable source of information

 

[Pumbaa]

Considering the power controllers in trains are notched, how difficult is it to hold the train at line speed? How far below line speed do you let the train get before you apply power again?

It depends on the train. On the Siemens EMU stock, the power controller is notched, but it is possible to incrementally increase power, so instead of 20, 40, 60, 80, 100%, you can hold it at 65% by moving the controller carefully.

Bombardier modern stock you definitely can't, and I'm not sure on DMUs. I'm under the impression that it's a no-can-do. I'm not sure on the 390s actually, Respite will tell if he's around.

 

[asylumxl]

As far as I know GPS sattelites do not offer elevation data only your position on the Earth's surface. It would have to be built into the GPS unit.

I don't believe so. That'd be incredibly useless. You're thinking of DEMs and they can be created by land surveying using GPS so. It may require a baseline (Datum/Benchmark) though.

 

[Pumbaa]

In reply to you Pumbaa, I swear I read such a thing on this forum, there was a thread about it a while back. But as we are both aware, railway forums are not always the most reliable source of information

It's probably true on older stock, but certainly not on the 390s. Digital readout beneath the speedo as well, there's no excuse.

If anyone gets the opportunity to visit any Alstom site, do. Their operation is fantastic, and they're very welcoming.

 

[Zoe]

I don't believe so. That'd be incredibly useless. You're thinking of DEMs and they can be created by land surveying using GPS so. It may require a baseline (Datum/Benchmark) though.

The GPS sattelites as far as I know just give you the position on the Earth's surface though so where is the elevation data from?