Ex-VTEC 91's for Blackpool - London Euston

[hooverboy]

A little tangentially: 91/Mk4 is 125mph stock. I know the WCML is not the straight racecourse the ECML is but I assume the 91/Mk4 stock would travel safely at 125mph on the WCML with the main effect being somewhat increased lateral forces on the passengers. Is this too great to tolerate? Or do 390/220/221 have markedly different running gear to allow 125 on more curved track. I know this isn't a practical suggestion, I am intrigued as to the reason.

the 390's have a bit of tilt built in,that's the secret.the tilt drastically reduces rail wear...think the way a motorcyclist can take insane corners by getting a knee down with very little apparent force.
I think the mk4's are capable of leaning into the curves, not sure about the 91's.

 

[Halish Railway]

But there are large straights on the WCML e.g. Cheddington, so why can't the 91's do 125mph there?

 

[a_c_skinner]

How can tilt of just the train body reduce rail wear? We cross posted about tilt BTW.

 

[a_c_skinner]

there are large straights on the WCML e.g. Cheddington, so why can't the 91's do 125mph there?

That wouldn't help, they'd need 125 throughout if they were to use the fast lines or they'd be caught by the EPS stock.

 

[Chester1]

I wonder what DB is thinking in regards to the WCML, it is allowing Alliance to waste time and money with little chance of success. While Alliance could never afford it by itself DB could have funded new tilting stock and intial losses in order to obtain long term WCML paths. I pressume Alstom intially took Alliance seriously because it is a DB subsidiary.

 

[Chester1]

Alliance is asking for multiple paths during the day which is very different. I am keen on an open access opperator on the WCML but there refusal to pay for new tilting trains has probably finished off the project. Its a shame the Cleethorpes service application was contingent on new Bradford via Leeds services. You would think leasing and maintaining the remaining four 180s in addition to a fleet of ten wouldn't have required huge amounts of new revenue to be viable. With Arriva / DB not biding for the WCML / HS2 franchise you would think they would be keen on establishing a foothold on the WCML.

 

[LNW-GW Joint]

A little tangentially: 91/Mk4 is 125mph stock. I know the WCML is not the straight racecourse the ECML is but I assume the 91/Mk4 stock would travel safely at 125mph on the WCML with the main effect being somewhat increased lateral forces on the passengers. Is this too great to tolerate? Or do 390/221 have markedly different running gear to allow 125 on more curved track. I know this isn't a practical suggestion, I am intrigued as to the reason.

There have been several statements made (eg by the SRA) over the years about raising some of the non-tilt speeds above 110mph on the WCML, but nothing has happened in practice.
But just off the main line, the Wolverhampton-Stafford line is both 125 PSR (originally for non-tilt XC Voyagers/HSTs) and 125 EPS, so it can be done.
I expect the arrival of HS2 non-tilt trains will force some kind of wider enhancement.
TPE's new 125mph CAF EMUs would also benefit.

 

[furnessvale]

How can tilt of just the train body reduce rail wear? We cross posted about tilt BTW.

I don't believe it does.

Tilt is all about passenger comfort. It does not alter cant deficiency, which has to reach a level far above what a passenger would tolerate before the train will climb over the rail and derail. Cant deficiency causes rail wear.

 

[ainsworth74]

The discussion about the Caledonian Sleeper moving out of Euston for HS2 construction work is off-topic and has been moved to a new thread which can be found here.

 

[randyrippley]

........I think the mk4's are capable of leaning into the curves, not sure about the 91's.

No, the tilt bogies intended for use with Mk4 sets on the WCML (not ECML) were never built. The existing ECML sets can't tilt

 

[a_c_skinner]

Cant deficiency causes rail wear

Thank you. So tilt could make rail wear worse, as you can get the right passenger lateral forces with less cant. Do we do that? Tamp the track for slower trains and use the tilt to make up for that?

 

[furnessvale]

Thank you. So tilt could make rail wear worse, as you can get the right passenger lateral forces with less cant. Do we do that? Tamp the track for slower trains and use the tilt to make up for that?

The amount of cant applied is always a compromise between slower trains bearing down on the inner rail and faster trains pushing up to the outer rail. Both will cause rail wear.
It is a commercial decision. Potential cost of rail and wheel wear -v- revenue gains with faster trains. Tilt is just one more factor in that decision process.

 

[driver_m]

But there are large straights on the WCML e.g. Cheddington, so why can't the 91's do 125mph there?

It’s not that long a straight, one end has a 90 PSR and the other in DVT days was a 100 PSR. The speeds would be up and down that much you’d be replacing the brakes ridiculously often.

 

[LNW-GW Joint]

After a decade or so of 125mph tilt on the WCML with 390/221 stock, I'd like to know how the route is faring in terms of wear and tear.
Those of us with long memories remember the steady decline on the WCML after the initial electrification honeymoon period.
This was when the upgrades of the early 1960s had been beaten up by a decade of the class 86 locos at 100mph.
Not to mention the increasingly fragile OHLE and power supply situation which led to significant diesel operation under the wires.
WCRM gave us a much more robust railway with a higher performance, and the stock used today should be much more track/OHLE-friendly.
I just hope the hard-pressed LNW maintenance guys are keeping pace with the ageing process of the assets.
The previous regime lasted essentially 40 years; one would like the current operation to last a good deal longer than that.
There should also be plenty of experience with the Class 91/Mk4 impact on the infrastructure after nearly 30 years of 125mph running on the ECML.

 

[driver_m]

After a decade or so of 125mph tilt on the WCML with 390/221 stock, I'd like to know how the route is faring in terms of wear and tear.
Those of us with long memories remember the steady decline on the WCML after the initial electrification honeymoon period.
This was when the upgrades of the early 1960s had been beaten up by a decade of the class 86 locos at 100mph.
Not to mention the increasingly fragile OHLE and power supply situation which led to significant diesel operation under the wires.
WCRM gave us a much more robust railway with a higher performance, and the stock used today should be much more track/OHLE-friendly.
I just hope the hard-pressed LNW maintenance guys are keeping pace with the ageing process of the assets.
The previous regime lasted essentially 40 years; one would like the current operation to last a good deal longer than that.
There should also be plenty of experience with the Class 91/Mk4 impact on the infrastructure after nearly 30 years of 125mph running on the ECML.

The last maintenance holiday that NR did, worked out badly as the trains were hammering the track. That was from one of the track inspectors who ride with us. I'd concur with that as the quality of track did go significantly worse before the track renewals recommenced. It's now a lot better again. But it has been prevented that it needs constant attention.

 

[hooverboy]

I don't believe it does.

Tilt is all about passenger comfort. It does not alter cant deficiency, which has to reach a level far above what a passenger would tolerate before the train will climb over the rail and derail. Cant deficiency causes rail wear.

it's about gyroscopic forces.
by altering the centre of gravity it will reduce the lateral(sideways) force on the side of the rail/flange contact that is trying to push the train away from the curve.
same technique with motorcycles and countersteering into a bend....the bend direction dictates which end of the handlebar you PUSH...to turn right, you push on the right bar, and the bike will dip.

 

[a_c_skinner]

IIRC one of the factors in the failure of the Lambrigg points was that the loading on the points was changed by re-tamping for higher speeds.

 

[furnessvale]

it's about gyroscopic forces.
by altering the centre of gravity it will reduce the lateral(sideways) force on the side of the rail/flange contact that is trying to push the train away from the curve.
same technique with motorcycles and countersteering into a bend....the bend direction dictates which end of the handlebar you PUSH...to turn right, you push on the right bar, and the bike will dip.

I am sorry but you are confusing active and passive tilt.
Modern trains use active tilt which does NOT move the centre of gravity.

 

[Mordac]

It does make sense for some to move. Otherwise you’ve got all of these services going from London to Birmingham:

2tph semi fast from London Marylebone
(Chiltern Railways)

3tph fast from London Euston
(Virgin Trains*)

3tph stopping from London Euston
(West Midlands Trains)

HS2 services from London Euston (goodness knows how many)

Plus there were rumours of a potential GWR service from London Paddington.

*We do not know if VT will still be operating this service at time of HS2

Birmingham, the centre of the World!

 

[Halish Railway]

Birmingham, the centre of the World!

Except if you have to get there on a voyager from Leeds.

 

[Bletchleyite]

I am sorry but you are confusing active and passive tilt.
Modern trains use active tilt which does NOT move the centre of gravity.

Correct. If it did a wrong side tilt failure could cause a derailment - that would be a very serious flaw.

 

[D6975]

Except if you have to get there on a voyager from Leeds.

Nahh.
HST to the Cross, 68 to Moor St
You know it makes sense.

 

[GRALISTAIR]

Class 91 haulage Preston to Blackpool sounds good

 

[edwin_m]

I am sorry but you are confusing active and passive tilt.
Modern trains use active tilt which does NOT move the centre of gravity.

The lateral force to steer a vehicle round a curve doesn't depend on the position of the centre of gravity, only on the square of the speed and inversely on the radius. Lowering the centre of gravity, and in the case of a motorbike moving it inwards, does reduce the tendency to overturn.

 

[furnessvale]

The lateral force to steer a vehicle round a curve doesn't depend on the position of the centre of gravity, only on the square of the speed and inversely on the radius. Lowering the centre of gravity, and in the case of a motorbike moving it inwards, does reduce the tendency to overturn.

Very handy for motorbikes, but as the centre of gravity on an active tilt train does not move when tilted, it is not applicable to trains.

Edited to add - continuing the motorbike analogy. If a train acted like a motorbike, imagine what would happen if tilt locked at whatever position it was in on a curve and the train stopped. Just like the motorbike it would fall over.

 

[CosherB]

So this thread is now going to turn into another litany of daft ideas for the future use of Mk4 stock?

 

[59CosG95]

So this thread is now going to turn into another litany of daft ideas for the future use of Mk4 stock?

Well, the forum needs something to rant about from the armchairs now that the future of the Class 442s' is secured!

 

[randyrippley]

Use them on Manchester - Scotland via WCML services instead of the capacity restrained EMUs
Of course if the trans Pennine routes ever do get electrified you could use them on the ECML from Manchester as well

 

[sprinterguy]

Use them on Manchester - Scotland via WCML services instead of the capacity restrained EMUs
Of course if the trans Pennine routes ever do get electrified you could use them on the ECML from Manchester as well

Both of those suggestions would seem to be moot when both routes will be receiving all new stock in the next couple of years, i.e. sooner than the class 91 will become available (and the TPE bi-mode sets that will be running up the ECML to Newcastle and Edinburgh will be able to use as much of the wires as is available from the get-go).

 

[a_c_skinner]

I've no idea how to run a railway (you all knew that of course) but it does seem to be curious economics that leaves the ECML electric rolling stock with no more than scrap value. Or is it really at scrapping age, it is 30?