Exceeding maximum line speed on LNER

[D365]

Where does the speed input to the speed limiter come from?
A sensor on an axle which could be inaccurate due to tyre turning

Surely it would be using the same speed signal as the speedometer.

 

[RJ]

Is this a Chiltern specific thing? I've never heard of this and I sign one of those traction (mind you, I've never tried this and don't think there's a 100mph stretch of track long enough to even threaten a 170 with getting to a ton, if it's even possible!).

On all the DMUs I sign (including some very new ones), there's no speed set, speed limiter or whatever traction restrike is - and a lot of them have CPBC.

CrossCountry Class 170s get nice, clear runs from a start to 100mph on departure from Cheltenham Spa to Worcestershire Parkway and from Worcestershire Parkway towards Bromsgrove. Truthfully I’m not sure where else on the network this can happen with 170s.

I frequently travelled on the 2207 Banbury to Marylebone and always enjoyed that run. That service was a starting point if you wanted to see what a Turbostar can do - one of the sections the train could do 0-100 unimpeded and it used to be an experience hurtling through the NW London suburbs at top speed with nothing in the way, though they have now added a stop at Wembley Stadium.

 

[XAM2175]

Where does the speed input to the speed limiter come from?
A sensor on an axle which could be inaccurate due to tyre turning, or doppler radar? Or is there another new method I don't know about?
I dont think GPS would be accurate enough.

Surely it would be using the same speed signal as the speedometer.

Most modern trains - and especially those with ETCS capability - will be using a combination of doppler radar and wheel revolution sensors.

 

[Pokelet]

How often do you get that out of them?

The only place I can think of would be after Kings Norton towards Bromsgrove going south on the fasts.

 

[trundlewagon]

The only place I can think of would be after Kings Norton towards Bromsgrove going south on the fasts.

It's only 90 along there.

Until the Stratford via Dorridges picked up Lapworth stops with the new timetable, they'd comfortably hit a ton between Dorridge and Hatton North.

Still a couple of trains a day that will do it (0551 to Stratford doesn't call at Lapworth and the 2330 from Stratford is fast between Wilmcote and Moor St).

 

[Bald Rick]

Imagine if some sort of spectacular tunnel was built avoiding york that could save 15 minutes too.

That would be spectacular, as it would have to include a time machine.

LNER services do the 15 miles from Colton Jn to Tollerton Jn in 15 minutes today including being stationary for 3 minutes. So to save 15 minutes, the Tunnel would have to enable a train to get from Colton to Tollerton in -3 minutes non-stop…

 

[Railperf]

Don't fall into the trap of thinking upgrading from 100 to 125 gets you loads of time, it doesn't. Its 7 seconds a mile ignoring acceleration and braking.

That's why good acceleration and braking are important. A Class 801 is around 53 seconds quicker from rest to 4 miles than a Class 91. And at the four mile mark the 91 is only doing 96mph, while the 801 is already doing 122mph. So by the time the 91 reaches 125mph it is even further behind. You'd have needed 15 to 20 miles of 140mph infrastructure to achieve the time savings that the 801's better acceleration delivers. Of course if there was 140mph running, the 801's would further romp into the distance. What trains like the 801 achieve is keep to the line speed profile much more efficiently - especially on short stretches of 125mph track - where HST's and Class 91's might never even reach 125mph.

There are definite improvements that can be made to increase lower speeds at many of the stations. Retford is a good example where 40mph turnouts into the loop platforms aid faster stopping and starting. But the superior performance of 80x means that on departure the turnouts would have been better upgraded to something capable of 50/60mph - yes it might only save a few seconds - but they all count on the railway.
Still our railways are pretty good compared to countries like Italy where many of the entrance / exits to mainline stations are mainly 30 km/h with some 60 km/h routes. The departure from Napoli Centrale is agonisingly slow. And so despite having a high-speed 186mph railway to Rome, lots of time is lost approaching/departing terminal stations - meaning average start-to-stop times are not much better than our 125mph routes.

 

[Tallguy]

The Azumas and associated fleets (IETs, 802s, 803s etc) are software limited to 124mph now but weren't when they were first introduced. There were a few overspeed incidents, one reaching as much as 148mph if I recall correctly, which is what led to the software change being implemented.

where/when was the 148mph incident please?

 

[Efini92]

where/when was the 148mph incident please?

There was 2. One was an LNER and one was a TPE.

 

[hexagon789]

where/when was the 148mph incident please?

Can't remember when the LNER incident was, but the TPE one was in Mid-November 2020, with an 802 exceeding 125mph for 165 seconds between York and Northallerton.

It was dark and the driver erroneously thought the speedset was active.

 

[Tallguy]

Can't remember when the LNER incident was, but the TPE one was in Mid-November 2020, with an 802 exceeding 125mph for 165 seconds between York and Northallerton.

It was dark and the driver erroneously thought the speedset was active.

Was the driver fired?

 

[hexagon789]

Was the driver fired?

No. Why would they be?

The key thing here is 'intent'.

The driver didn't deliberately intend to exceed the permitted speed and as soon as they realised their mistake, took corrective action and self-reported the incident.

 

[172007]

How often do you get that out of them?

Was daily on Stratford OA's via Dorridge but in the bew timetable the Lapworth stop scuppers that. Still do it on ECS moves to Dorridge, just.

 

[DanNCL]

Was the driver fired?

It would normally only be announced publicly that someone had been sacked if there was a very good reason to do so, for example if they had received a prison sentence, and even then it wouldn’t always be made public.

 

[Eastern Farmer]

Sorry to post on here after it not being used for a long while but I have got a somewhat related question to do with LNER 80xs. I did post a thread as this didn’t come up after my initial searches so again apologies.
So my question is in real life do all the class 80xs have speed set and if not which do and also is the speed set feature actually used in real life (for LNER specifically) by drivers and if it is do they set it straight to 125 or adjust it as can be done in TSC (sorry). If that is a yes is it a policy thing or a drivers choice. Any knowledge is very much appreciated so thanks for any respeonses.

 

[hexagon789]

Sorry to post on here after it not being used for a long while but I have got a somewhat related question to do with LNER 80xs. I did post a thread as this didn’t come up after my initial searches so again apologies.
So my question is in real life do all the class 80xs have speed set and if not which do and also is the speed set feature actually used in real life (for LNER specifically) by drivers and if it is do they set it straight to 125 or adjust it as can be done in TSC (sorry). If that is a yes is it a policy thing or a drivers choice. Any knowledge is very much appreciated so thanks for any respeonses.

Since modifications were made in the aftermath of the TPE overspeed incident between Darlington and York, all 80x speedset (they are all fitted) are permanently active and automatically restrict to a 125mph ceiling. There is nothing to stop a driver manually controlling speed within this upper limit and having read some accounts by GWR drivers on another forum, it appears some do prefer that method.

 

[Eastern Farmer]

Since modifications were made in the aftermath of the TPE overspeed incident between Darlington and York, all 80x speedset (they are all fitted) are permanently active and automatically restrict to a 125mph ceiling. There is nothing to stop a driver manually controlling speed within this upper limit and having read some accounts by GWR drivers on another forum, it appears some do prefer that method.

Thanks for that info mate.

 

[Deepgreen]

The Azumas have the speedset (like cruise control on cars), hardwired to be both permanently on and unable to be set above 125mph.

In practice due to rounding the actual maximum as mentioned above is 123-123.5mph.

While the tolerance is 201km/h (the 124.89mph quoted above), the system works in whole mph. Ie 123.6 is 124mph, 123.4 would be 123mph.

Power dials off about 1mph before the set speed, so the balancing speed ends up being about 1-2mph below that set.

Does that mean they couldn't easily be modified to get to, say, 140mph if line speed was raised?

 

[hexagon789]

Does that mean they couldn't easily be modified to get to, say, 140mph if line speed was raised?

AFAIAA the '125 ceiling' was done just through a software update; so another update would presumably restore the design ceiling.

 

[RichW1]

A speed limiter applies at 124.89mph.

RIP Great western 125mph.... (IETs to have speed limiter automatically set)

As of next week all GWR IETs will have the speed limited set automatically to 125mph (in practice this keeps the train at 124mph due to the difference between mph and kph). So no more 125mph on the Western :-(

www.railforums.co.uk

This drives me absolutely insane. It is as though they are being pedantic and annoying on purpose. Pendolinos are 129mph before the limiter. Would it really kill them to program it for the same speed so they actually can be driven at 125mph with a couple of mph available? Who made this decision?! The mindset to do this I just do not understand. There is precedent, the railways have run faster for decades, to suddenly make it so these don’t go above 123mph in reality is just indicative of a culture.

 

[zwk500]

This drives me absolutely insane. It is as though they are being pedantic and annoying on purpose. Pendolinos are 129mph before the limiter. Would it really kill them to program it for the same speed so they actually can be driven at 125mph with a couple of mph available? Who made this decision?! The mindset to do this I just do not understand. There is precedent, the railways have run faster for decades, to suddenly make it so these don’t go above 123mph in reality is just indicative of a culture.

Wasn't this done in response to several overspeeding incidents?

 

[3RDGEN]

Wasn't this done in response to several overspeeding incidents?

After the Croydon Tram crash First Group got touchy about overspeed control, as a significant operator of 80x's I suspect that may be behind it, the incidents on the ECML will not of helped.

With modern electronics you can limit speed far more accurately so why not do it to cover everyone?

 

[notadriver]

This drives me absolutely insane. It is as though they are being pedantic and annoying on purpose. Pendolinos are 129mph before the limiter. Would it really kill them to program it for the same speed so they actually can be driven at 125mph with a couple of mph available? Who made this decision?! The mindset to do this I just do not understand. There is precedent, the railways have run faster for decades, to suddenly make it so these don’t go above 123mph in reality is just indicative of a culture.

It’s quite rare to see Pendolinos doing 125 mph it’s also usually around 123 mph. I’m sure the Speedo in an 80x shows an indicated 124-125 mph. In France it’s common to operate 5 kph below the max permitted speed.

 

[PudseyBearHST]

Wasn't this done in response to several overspeeding incidents?

That’s not the point he’s making though. He’s not arguing about having a speed limiter.

It’s quite rare to see Pendolinos doing 125 mph it’s also usually around 123 mph. I’m sure the Speedo in an 80x shows an indicated 124-125 mph. In France it’s common to operate 5 kph below the max permitted speed.

That’s not true. It’s only if speed set is used, then you’ll sit just below 125mph otherwise you can quite easily hold it at 125mph manually.

 

[notadriver]

That’s not true. It’s only if speed set is used, then you’ll sit just below 125mph otherwise you can quite easily hold it at 125mph manually.

Most logs I’ve seen are around 123 mph so I would guess most drivers use speed set on a Pendolino.

 

[PudseyBearHST]

Most logs I’ve seen are around 123 mph so I would guess most drivers use speed set on a Pendolino.

Interesting to know, thanks