Max speed...

[stu227]

I have a question which I'm sure someone here will easily answer...

Is it possible for a regular passenger train (pendolino in this case) to exceed the max line running speed?

I ask because we were on a late running service yesterday which made up about 15 minutes of lost time. We seemed to be flying so I turned on a GPS Speedo and it hit 131mph.

It could just have been a glitch in the GPS I guess, but it made me wonder whether trains are limited, or if the driver can actually just let rip?!

 

[martin2345uk]

Possible - yes
Allowed - no
Inaccurate GPS - highly possible

 

[EZJ]

I can't speak for a pendo but the two types of traction I drive will either cut the power off at 3mph over its max speed or dump the brakes at 6 mph over.

 

[martin2345uk]

Exceeding the traction's max speed is different to exceeding the linespeed though

 

[Watershed]

I have a question which I'm sure someone here will easily answer...

Is it possible for a regular passenger train (pendolino in this case) to exceed the max line running speed?

I ask because we were on a late running service yesterday which made up about 15 minutes of lost time. We seemed to be flying so I turned on a GPS Speedo and it hit 131mph.

It could just have been a glitch in the GPS I guess, but it made me wonder whether trains are limited, or if the driver can actually just let rip?!

As with many things - it depends.

Overspeeding on a Pendolino would be essentially impossible, certainly at that speed range, because the only lines on which they are allowed to run at 125mph are fitted with TASS, a balise based system which controls the tilt as well as preventing overspeeds. IIRC it applies the brakes if the speed exceeds 127mph. Pendolini are rated for 140mph FWIW.

However on other lines it's very much possible - the speed boards are shown on the trackside, but with in cab signalling only existing on a handful of routes (Cambrian, Thameslink and Elizabeth Line core, HS1, Moorgate branch and GWML out to Heathrow) there is often nothing stopping a driver from overspeeding, within the capabilities of their train.

ATP also exists on the GWML out to Bristol and the Chiltern line to Aynho Jn and provides a similar level of speed supervision, although not all trains are fitted with it.

On approach to any significant reduction in speed, there are TPWS (and sometimes TPWS+) OSS loops which automatically apply the emergency brakes if a train passes over them at above the threshold speed. But again, these wouldn't stop an overspeed at other locations, only at that specific point.

An inaccurate reading on your GPS is much more likely. It's also worth noting that 99.9% of drivers are highly professional people who wouldn't dream of speeding (and putting their career on the line) to make up time.

 

[Basil Jet]

We seemed to be flying so I turned on a GPS Speedo and it hit 131mph.

I find the idea that any human could perceive a difference between 125mph and 131mph implausible.

 

[Horizon22]

Over people have recorded data like this before, and it's known that your cheapo GPS figures from an app will be a lot less accurate than the driver's speedometer in the cab of a multi-million pound train.

 

[stu227]

As with many things - it depends.

Overspeeding on a Pendolino would be essentially impossible, certainly at that speed range, because the only lines on which they are allowed to run at 125mph are fitted with TASS, a balise based system which controls the tilt as well as preventing overspeeds. IIRC it applies the brakes if the speed exceeds 127mph. Pendolini are rated for 140mph FWIW.

However on other lines it's very much possible - the speed boards are shown on the trackside, but with in cab signalling only existing on a handful of routes (Cambrian, Thameslink and Elizabeth Line core, HS1, Moorgate branch and GWML out to Heathrow) there is often nothing stopping a driver from overspeeding, within the capabilities of their train.

ATP also exists on the GWML out to Bristol and the Chiltern line to Aynho Jn and provides a similar level of speed supervision, although not all trains are fitted with it.

On approach to any significant reduction in speed, there are TPWS (and sometimes TPWS+) OSS loops which automatically apply the emergency brakes if a train passes over them at above the threshold speed. But again, these wouldn't stop an overspeed at other locations, only at that specific point.

An inaccurate reading on your GPS is much more likely. It's also worth noting that 99.9% of drivers are highly professional people who wouldn't dream of speeding (and putting their career on the line) to make up time.

Wonderful reply, exactly what I was hoping for! Cheers.

I find the idea that any human could perceive a difference between 125mph and 131mph implausible.

Which is probably why it's a good job we have speedometers fitted to things!

 

[LNW-GW Joint]

As far as I understand it, class 805/807s will soon be running at 125mph on the WCML without EPS or TASS controls, which seems like a backward step.
That's no different to 80x on the ECML, but it's still a lower level of speed control/ATP to Pendolinos with TASS.

 

[yorkie]

I have a question which I'm sure someone here will easily answer...

Is it possible for a regular passenger train (pendolino in this case) to exceed the max line running speed?

I ask because we were on a late running service yesterday which made up about 15 minutes of lost time. We seemed to be flying so I turned on a GPS Speedo and it hit 131mph.

It could just have been a glitch in the GPS I guess, but it made me wonder whether trains are limited, or if the driver can actually just let rip?!

Possible but extremely rare.

There was an incident on TPE which was documented on here; I will see if I can dig the link out later.

In your case it will almost certainly be an inaccuracy in the GPS readings; this is extremely common.

 

[Horizon22]

Possible but extremely rare.

There was an incident on TPE which was documented on here; I will see if I can dig the link out later.

In your case it will almost certainly be an inaccuracy in the GPS readings; this is extremely common.

Its here (at least this is I believe the incident you were thinking of) - https://www.railforums.co.uk/threads/a-tpe-class-802-got-up-to-145mph-a-record.211675/

 

[dan4291]

LNER and TPE have both had overspeed incidents in the past on the ECML involving the Hitachi 80x sets, 143 and 145mph respectively I think. The 80x sets have a speed limiter that sometimes has to be manually set by the driver, so there's scope for the driver to forget, although only realising once you're nearly 20mph over the limit is a bit concerning!

 

[GB]

I find the idea that any human could perceive a difference between 125mph and 131mph implausible.

Probably, but that is not what the OP suggested.

 

[Horizon22]

LNER and TPE have both had overspeed incidents in the past on the ECML involving the Hitachi 80x sets, 143 and 145mph respectively I think. The 80x sets have a speed limiter that sometimes has to be manually set by the driver, so there's scope for the driver to forget, although only realising once you're nearly 20mph over the limit is a bit concerning!

Although the ECML doesn't have ATP, so a GWR 80x couldn't do the same.

 

[Efini92]

I have a question which I'm sure someone here will easily answer...

Is it possible for a regular passenger train (pendolino in this case) to exceed the max line running speed?

I ask because we were on a late running service yesterday which made up about 15 minutes of lost time. We seemed to be flying so I turned on a GPS Speedo and it hit 131mph.

It could just have been a glitch in the GPS I guess, but it made me wonder whether trains are limited, or if the driver can actually just let rip?!

There was a software mod on them years ago, once the pendolino reaches 128 it will start throwing alarms out with bogie instability fault.

 

[gg1]

A related question.

How accurate are modern train speedometers and how regularly are they calibrated?

 

[DanNCL]

Certainly more likely with some trains than others. A 390 will as mentioned above not be able to achieve more than a few mph above the speed limit because of TASS. Anything on the GWML will be similarly restricted through ATP, and anything on HS1 similarly restricted through TVM - on a 395 this includes limiting the unit to 225kph on 300kph sections of line.

91s, 800s, 801s and 802s have all had incidents of running at above 130mph on the ECML in recent years, the most common cause is the driver thinking speed set was on when it wasn't. There have also been incidents where 90s were taken up to 125mph on the ECML when being driven from the DVT.

 

[Snow1964]

A related question.

How accurate are modern train speedometers and how regularly are they calibrated?

Digital speedometers are fairly accurate if set up properly. But the set up needs to know the wheel diameter of the wheel set that they are run from.

In theory every time the relevant wheels get reprofiled (on a wheel wheel) the speedo should be recalibrated.

With a wheel of about 880mm (from memory are 890mm when new) taking 4mm off surface will reduce diameter 8mm or about 1%. Obviously at 125mph, 1% is 1.25mph, so if they miss a reprofile or about 10mm surface is lost, could be about 3% out. And logically if initially were 1 or 2% out of true then could get to 5-6mph out of true

 

[driver9000]

LNER and TPE have both had overspeed incidents in the past on the ECML involving the Hitachi 80x sets, 143 and 145mph respectively I think. The 80x sets have a speed limiter that sometimes has to be manually set by the driver, so there's scope for the driver to forget, although only realising once you're nearly 20mph over the limit is a bit concerning!

Since those incidents the TPE 802s now have the limiter set to 125mph as a default setting. If the Driver wants to set it lower then they have to change it manually.

 

[John Luxton]

During the Autumn 2021 TPE Club 55 Promotion I took a day trip from Liverpool to Newcastle on an Nova 1 / 802 and took my GPS with me which I normally use when on board ships and ferries.

First time I had used it by rail and only decided to do so when observing some railtour participants recording rail speeds a few weeks previously.

The max I recorded with the GPS for the ECML just north of York was 131MPH for 45 seconds a few miles north of York.

 

[Peter Mugridge]

Most GPS units are accurate to +/- 1%

If you have a train running at 125mph plus the possible 3mph over, i.e. 128mph, adding 1% on to that gives 129.8mph which is very close to 131mph; so the GPS doesn't even need to be faulty to display 130mph and an extra 1mph is easily explained by the signal getting slightly interefered with - trees are a frequent culprit, as are tall buildings. A reflected GPS signal can confuse the receiving unit.

 

[Huntergreed]

Is the TASS system on pendolino’s used to prevent the train overspeeding at all (I.e. would it kick in at 103 in a 100) or does it only work for 125 sections?

 

[Efini92]

Is the TASS system on pendolino’s used to prevent the train overspeeding at all (I.e. would it kick in at 103 in a 100) or does it only work for 125 sections?

Works anywhere where tass is fitted. The 15 at Wolverhampton is very sensitive.

 

[43066]

135mph ish in an HST (keep the tap wide open when necessary).

Official? (no).

Enjoyed? (absolutely).

I simply win this discussion.

 

[Efini92]

135mph ish in an HST (keep the tap wide open when necessary).

Official? (no).

Enjoyed? (absolutely).

I simply win this discussion.

I think the medals go to the LNER and TPE drivers who reached 140. Plus all the drivers that initially trained 390’s that got them upto 140 as part of the training. Then there’s all the drivers that drive hst’s pre data recorders.
But other than that I guess you won.

 

[43066]

I think the medals go to the LNER and TPE drivers who reached 140.

I don’t think so.

Plus all the drivers that initially trained 390’s that got them upto 140 as part of the training. Then there’s all the drivers that drive hst’s pre data recorders.
But other than that I guess you won.

I just about snuck in there…

Best thing I’ve done in my life. To take command of an HST. Thoroughly enjoyed.

 

[Wapps]

As far as I understand it, class 805/807s will soon be running at 125mph on the WCML without EPS or TASS controls, which seems like a backward step.
That's no different to 80x on the ECML, but it's still a lower level of speed control/ATP to Pendolinos with TASS.

As far as I understand it, class 805/807s will soon be running at 125mph on the WCML without EPS or TASS controls, which seems like a backward step.
That's no different to 80x on the ECML, but it's still a lower level of speed control/ATP to Pendolinos with TASS.

No, they will do 110mph max, same as the 350s. That’s the backwards step here.

 

[8J]

I believe LNER hold the record for the highest overspeed incident at above 150mph. I can't recall the exact speed it reached but I do remember it happening.

As pointed out, TPE's 802 units have max speed limiters of 125mph that can't be disabled by the driver.

 

[cambsy]

As posters, have said, the 390’s, will only do 127-128mph, as the TASS system, will brake above this speed, and it cant be overridden etc, as I was on the Heavens Angels special, which tried to beat the APT, 3hr 52 min record, for London-Glasgow, and we couldn’t get around, the TASS, so the record wasn’t broken, but it was a close thing.

I had back in the 90’s, before data recorders etc, a few runs, with the 91’s, on ECML, hitting speeds of 135-140mph, when making up time on the 3hr 59 mins, London-Edinburgh timings, and there are logs of these sort of runs, done by expert train recorders. I have also had other excessive speed runs, with various traction, one of my most notable, was a 47/8, on a Holyhead-Euston relief, non stop Holyhead-Chester, which managed to, cab ride, from Holyhead to Chester, hitting 99 mph on Anglesey, then continuing at 90mph on to Chester, the driver was a bit of a nutter.

Though I haven’t had any really excessive speed runs, with HST’s, there are a few documented runs of 135-140mph, between Paddington-Bristol, soon after they came out, in the late 70’s, before fitted with limiters etc, when their was an un official 140mph club, Which persisted with the 91’s, but though potentially a driver could speed nowadays, they dont, as too much risk of losing job if they do, though ive seen couple logs, of 129 mph, not that many years ago, with various traction.

 

[507020]

No, they will do 110mph max, same as the 350s. That’s the backwards step here.

Pre-covid, there were talks between Network Rail, TPE, CAF and Hitachi about allowing 397s and 802s to run at 125mph on the WCML without tilting by making use of their superior acceleration to Pendolinos, but I don't know what happened to them after 2020. The 805/807s are yet another new development, but given that they won't go north of Weaver Junction, is there nowhere they will run at 125mph using separate timings from Pendolinos or 350s, even Stafford - Wolverhampton?