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TPE Class 397 ('Nova 2') construction and updates

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a_c_skinner

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cant deficiency and the forces on passengers are the main reason 125 is not allowed without tilt

Tilt was specified for 140mph, so I do wonder if it is mandatory for 125mph is to save face...

There are points on the WCML where it plainly makes a big difference to passenger comfort, Crewe to Stafford IIRC is a good example, but I suspect there are lots of places where it makes a lot less difference.
 

hexagon789

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Tilt was specified for 140mph, so I do wonder if it is mandatory for 125mph is to save face...

There are points on the WCML where it plainly makes a big difference to passenger comfort, Crewe to Stafford IIRC is a good example, but I suspect there are lots of places where it makes a lot less difference.

Well the APT-P was specified for tilt for both the 125 and 155mph versions, but for 125mph only there are definitely places where you could do 125 without tilt or even 5 or 10 mph over the non-EPS speed and I doubt you'd notice it comfort wise. The tighter curves are of course the issue but if it's definitely going ahead that the 397s will be allowed to use some EPS speeds, it will be interesting to see if they are all on fairly straight bits of track or what.
 

a_c_skinner

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Staying on this, what work has been done on how much cant deficiency is too uncomfortable? Other forms of transport tolerate much more marked extraneous forces on the passengers and the main issue for me on trains is sudden jolts not sustained yet modest sideways forces.
 

Peter Mugridge

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Staying on this, what work has been done on how much cant deficiency is too uncomfortable? Other forms of transport tolerate much more marked extraneous forces on the passengers and the main issue for me on trains is sudden jolts not sustained yet modest sideways forces.

Before the French extended their high speed line from Tours to Bordeaux a couple of years ago, the TGVs were running on the classic line below Tours at up to 135mph through curves that are similar to what the Trent Valley and Weedon lines were like before they were straightened out a bit. Having been on those TGVs on that classic line at those speeds, I would say it's rather more comfortable than the tilting on the West Coast line is.
 

Spartacus

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Staying on this, what work has been done on how much cant deficiency is too uncomfortable? Other forms of transport tolerate much more marked extraneous forces on the passengers and the main issue for me on trains is sudden jolts not sustained yet modest sideways forces.

It’s a difficult one to answer as it’s down to personal preference and how much people are used to it. For instance passengers might complain of the ride on faster 397s initially but then get used to it just as they did when 185s were introduced.

As for other forms of transport, their forces tend to be a less controllable such as the rocking of a ship, unreasonable to prevent such as aircraft acceleration on takeoff, or self inflicted in a car.
 

LNW-GW Joint

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When the WCML went to 110mph from 100mph, there were certainly places where you could feel the centrifugal force (eg Weedon and Whitmore with their reverse curves), and wouldn't want to go faster non-tilt.
On a bad day there was plenty of smashed crockery in the restaurant car.
It's all been re-engineered since of course, and the tilt works well.
There's also the maintenance issue, where higher non-tilt speeds will cause more track wear and "creep", even if the higher speed is "safe".
 

driver_m

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When the WCML went to 110mph from 100mph, there were certainly places where you could feel the centrifugal force (eg Weedon and Whitmore with their reverse curves), and wouldn't want to go faster non-tilt.
On a bad day there was plenty of smashed crockery in the restaurant car.
It's all been re-engineered since of course, and the tilt works well.
There's also the maintenance issue, where higher non-tilt speeds will cause more track wear and "creep", even if the higher speed is "safe".

Weedon is 100 though for non tilt even now. Never known it a lower speed even though I have heard it used to be 80 many moons ago.
 

a_c_skinner

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There's also the maintenance issue,

Obviously faster means track forces change (increase, forgetting balancing speed) but tilt doesn't alter track forces and I think we are disussing changes in lateral forces that most people wouldn't notice most of the route.
 

Railperf

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Before the French extended their high speed line from Tours to Bordeaux a couple of years ago, the TGVs were running on the classic line below Tours at up to 135mph through curves that are similar to what the Trent Valley and Weedon lines were like before they were straightened out a bit. Having been on those TGVs on that classic line at those speeds, I would say it's rather more comfortable than the tilting on the West Coast line is.
If I recall correctly, SNCF trains run at much higher cant levels than Uk stock, which allows for slightly higher speeds and reduces the need for tilt.

Tilt in the Uk seems to more clinically applied than overseas. Italian Pendolino's for example seem to respond to the curve in a passive way - whereas Uk pendolino's seem to actively have the tilt levels set by the trackside balises - stand to be corrected if I am wrong.
I was once aboard an ETR 485 pendolino between Rome and Bari - traversing the sinuous single line track between Caserta and Benevento. It was clear that tilt on one of the intermediate vehicles was not working - and yet the train continued to run at Pendolino limits rather than revert to the slightly lower limits - which would have been 105km/h instead of 115km/h. and as a result, it didn't seem to adversely affect comfort levels, even though it was strange to see the difference in coach tilt angle between the tilt and non tilting coach.
There are still some tilt speed boards in France between Modane and Chambery that display higher speeds for Pendolino trains as opposed to normal stock - even though it is a long time since the Italians stopped running their ETR460 Pendolino into France.
 
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Peter Mugridge

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If I recall correctly, SNCF trains run at much higher cant levels than UK stock, which allows for slightly higher speeds and reduces the need for tilt.

There was certainly a quite strong sideways feel on those curves - and that definitely felt a lot more comfortable to experience than the tilt on the 390s.
 

Roast Veg

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From a safety perspective it was said that having more than three different speed limits in one area was too complex, and on the WCML there are places where the heavy freight speed, permissible speed, and enhanced persmissible speed are all different - so you can't also add an "HST" differential for well braked high speed units (which I suppose the 397s would fall under?). There would be scope for raising some line speed above 110mph for MU differentials under the Permissive Speed signage though.
 

Railperf

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From a safety perspective it was said that having more than three different speed limits in one area was too complex, and on the WCML there are places where the heavy freight speed, permissible speed, and enhanced persmissible speed are all different - so you can't also add an "HST" differential for well braked high speed units (which I suppose the 397s would fall under?). There would be scope for raising some line speed above 110mph for MU differentials under the Permissive Speed signage though.
Italian railways use as many as four differential speed limits and that seems to work okay. Each driver is given a 'scheda treno' for his consist which confirms the speed limits he has to comply with en route as well as stopping and passing times. Lineside marker boards display three speed ranges A B and C and then a fourth speed limit range P 'Pendolino' is posted within the Italian sectional appendix ' fascicolo linea' as well as the drivers scheda treno.
There is no good reason we could not do the same here. DAS units can also be used to display the consist speed limit in the cab.
 

supervc-10

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From a safety perspective it was said that having more than three different speed limits in one area was too complex, and on the WCML there are places where the heavy freight speed, permissible speed, and enhanced persmissible speed are all different - so you can't also add an "HST" differential for well braked high speed units (which I suppose the 397s would fall under?). There would be scope for raising some line speed above 110mph for MU differentials under the Permissive Speed signage though.

Surely this is just a change of the permissible speed from 110 to 125?
 

Spartacus

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Surely this is just a change of the permissible speed from 110 to 125?

Not necessarily, it might end up being specific to 397s, but even if it was a general HST speed the 110mph would still apply for any services that fitted into the gap, even if there's no booked traffic that it applied to.
 

hexagon789

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If I recall correctly, SNCF trains run at much higher cant levels than Uk stock

I think much of the continent does. Though iiirc it was raised here to allow 110 on the WCML by 2 inches and possibly elsewhere.

Italian railways use as many as four differential speed limits and that seems to work okay. Each driver is given a 'scheda treno' for his consist which confirms the speed limits he has to comply with en route as well as stopping and passing times. Lineside marker boards display three speed ranges A B and C and then a fourth speed limit range P 'Pendolino' is posted within the Italian sectional appendix ' fascicolo linea' as well as the drivers scheda treno.
There is no good reason we could not do the same here. DAS units can also be used to display the consist speed limit in the cab.

Very true, but I think ideally you'd have as few different speed categories to simply things. Ideally you'd simply make any section which could support higher speeds for the 397s either a blanket higher limit for all trains or all-non tilting trains or perhaps use HST differentials which I imagine 397s could likely use.
 

themiller

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So when does that put them in service?
I was told by a TPE chap alongside a 397 on a test working that it’ll be towards the end of the year due to training of crews. TPE will be particularly affected by this because of having to train staff on 3 new train types.
 

superkev

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I was told by a TPE chap alongside a 397 on a test working that it’ll be towards the end of the year due to training of crews. TPE will be particularly affected by this because of having to train staff on 3 new train types.
Dont West Midlands want the 350s in September which is getting close.
K
 
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