Keeping to the speed limit

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ryan125hst

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I've just been watching a video on You Tube which shows an East Coast HST doing 130mph just north of Peterborough. The user also mentions the fact that their friends phone was also showing this, so it is unlikely it is a problem with the phone.

http://www.youtube.com/watch?v=VlruU5VQlAg

Do train drivers sometimes slightly exceed the speed limit. It's not as if it was driven it flat out at 140mph or more, but it is still speeding. I thought the TPWS would stop this, and of course the OMTR would prove it as well.
 
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heart-of-wessex

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I dunno, me being me I would say the app isn't 100% anyway, I don't go by maps/GPS much, just useful as an rough estimate. Nothing wrong with the classic counting down the mileposts!

I had a look at that EC map for example, tracking down the Edinburgh - Kings Cross which, apparently, was doing 150mph through Dunbar, 120mph through Morpeth (And stayed on track somehow!!) and other various speeds, some touching over the limit of the track too. So that was accurate then....

I thought too that TPWS or something would slow things down?
 

DaveNewcastle

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This is a subject which seems to crop up quite regularly so I guess it must be of great fascination. Here are three threads where this has been discussed, though some of the posts should not be taken at face value! It seems to me that some posters simply want this to be true (and every little assistance such as readings from a consumer GPS moving at speed seems to help make their wishes come true!).

rough riding on East coast when 225's did 140mph in mid 90's

HST passing Slough at 138mph

Speeding...
 

brad465

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I think you can go over by a small margin, like with most road speed cameras. But the driver would need to be careful, in instances like coming round hard bends where speeds are low anyway (but speeding could be more of a problem) or approaching stations/red signals.
 

DXMachina

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It may happen in the oddest of places.. a few months back I was on a Metropolitan line train leaving Harrow-o-T-H shortly before a Chiltern diesel did

As the 165 caught up the Met driver dropped the hammer. A-Stock on a good day can't half go and when a few other passengers expressed alarm I flicked on a phone GPS [usual caveat about reliability] and recorded the train accelerating to 78mph before settling down to a steady 70

(all London Transport lines have a 50mph limit but the As were designed for 75 and allegedly capable of 108 per someone I know who used to drive them)

Overtook the Chiltern rail train in full after it had got right past us...
 

KA4C

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I thought too that TPWS or something would slow things down?
TPWS overspeed loops are fitted on the approach to certain PSR's to ensure that train speed has been reduced towards the new permitted speed, and on the approach to certain signals, operable when the signal is at danger, to ensure that approach speed to the signal at danger is not excessive

I do, however, wish that some people would not act like excited kids and post stuff like this on youtube, it only sets the trialbyyoutube brigade off and could result in a driver being under investigation for no good reason. At least OTDR is more accurate, within parameters, than some children's mobile phones
 

hairyhandedfool

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Older trains use analogue speedometers (don't know about newer ones or refurbs), which can be a little inaccurate, I think Thameslink accepted that they could be upto 3% out, which at 130mph is 4.2mph, couple that with a speedo dial that isn't exactly precisely marked and any slight discrepancies in the app, I reckon you could easily find 5mph.
 

KA4C

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Older trains use analogue speedometers (don't know about newer ones or refurbs), which can be a little inaccurate, I think Thameslink accepted that they could be upto 3% out, which at 130mph is 4.2mph, couple that with a speedo dial that isn't exactly precisely marked and any slight discrepancies in the app, I reckon you could easily find 5mph.
and don't forget the wheel diameter offset

when looking at an OTDR download, if wheel diameter has not been checked, the assessor will allow for this by using an offset against the speed
--- old post above --- --- new post below ---
Do train drivers sometimes slightly exceed the speed limit. It's not as if it was driven it flat out at 140mph or more, but it is still speeding.
Driver's are expected to comply with speed limits. However, speed can creep up and go over a bit. When looking at an OTDR, the assessor would expect to see the driver recognise this and take action to correct it, they would also not expect to see it happening all of the time
 

LE Greys

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Older trains use analogue speedometers (don't know about newer ones or refurbs), which can be a little inaccurate, I think Thameslink accepted that they could be upto 3% out, which at 130mph is 4.2mph, couple that with a speedo dial that isn't exactly precisely marked and any slight discrepancies in the app, I reckon you could easily find 5mph.
There was a story in the Railway Magazine last month about a Deltic driver who got into hot water for being caught at 112 mph. Luckily for him, they found out at the next A-Exam that they speedo was seriously under-readiing (although whether that was too convenient is not mentioned).

Fastest I've ever done on a service train is a pair of 27-second miles between Didcot and Swindon, which works out at 133 mph. There was also a 24-second mile on Stoke Bank (150 mph), but that could have been a mistake by me, and anyway the train hit signals just before Helpston, so it's unconfirmed.
 

Ploughman

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Dont forget that mileposts may not be accurate either.
I have found them to be up to 80 yards out of place.
 

Dieseldriver

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It may happen in the oddest of places.. a few months back I was on a Metropolitan line train leaving Harrow-o-T-H shortly before a Chiltern diesel did

As the 165 caught up the Met driver dropped the hammer. A-Stock on a good day can't half go and when a few other passengers expressed alarm I flicked on a phone GPS [usual caveat about reliability] and recorded the train accelerating to 78mph before settling down to a steady 70

(all London Transport lines have a 50mph limit but the As were designed for 75 and allegedly capable of 108 per someone I know who used to drive them)

Overtook the Chiltern rail train in full after it had got right past us...
Was that northbound or southbound?...
 

DXMachina

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Was that northbound or southbound?...
Northbound.The Met driver kept in the 70mph range 'til near Northwood then coasted down to high 40s before starting braking for Moor Park

Hang on a minute. Think I might be confusing my stations here actually - it was where there's a separate 2 tracks for Chiltern rail services that the overtake happened.
 

table38

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Spookily I was thinking about this the other day, because if GPS works out your lat/long position and interprets your speed from that, it's actually measuring the flat distance.

So if you are on a gradient, I'd imagine your speed is actually slightly higher - but I never bothered doing the maths to see!

Unfortunately taking worst case (Lickey at 1 in 37.7) I calculate by my dodgy maths that it's only 0.0352% faster :(
 

GadgetMan

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Speedos on trains are often out. It is not unusual to notice a +/- 7-10 mph difference in speedo readings between the leading and rear cab.
 

KA4C

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170's have a 3mph 'swing' in the speedo reading.

If a set is downloaded and the driver had'nt reacted to going over the psr then Im sure there will be a please explain waiting for him.
A please explain? You mean they don't sit down with the driver and go through the download if they find a discrepancy?
 

tirphil

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Its also worth mentioning that 66's have three speedo readings in each cab and none of them will report the same speed. Speedo on the dash panel, speedo on the Q-Tron and speedo on the EM2000. 60's only have dash and Q-Tron speedo's. Don't sign 43's or 91's so can't comment on those though.
 

causton

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Spookily I was thinking about this the other day, because if GPS works out your lat/long position and interprets your speed from that, it's actually measuring the flat distance.

So if you are on a gradient, I'd imagine your speed is actually slightly higher - but I never bothered doing the maths to see!

Unfortunately taking worst case (Lickey at 1 in 37.7) I calculate by my dodgy maths that it's only 0.0352% faster :(
I thought most GPS devices also found altitude?
I mean, if the one on my phone does... :P
 

jon0844

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Fastest train I've been on in the UK before HS1 (and excluding Eurostar) was a Mk4 GNER train around 2003, coming back to London from Edinburgh on a Sunday evening and running late, due to an incident not long after starting. GPS measured it at a range of 135-140mph for a fair run, north of Peterborough. Made up quite a bit of time, but even with that and the padding in the timetable, it still didn't make it all up!

The other day, I got another chance to go on a 313 that was running a semi-fast service (Potters Bar, next stop Finsbury Park) and was shunted out onto the fast. It peaked at 80mph for a short time, but stuck around the 78mph mark. They've got a top speed of 75mph but presumably are far too old to have a limiter. They really do move when given a chance!

I wonder if 365s have more accurate speedos and limiters as I don't think I've ever recorded one doing more than 101mph. Pretty much spot on.
 

Skymonster

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I thought most GPS devices also found altitude?
I mean, if the one on my phone does... :P
Yes they do, including many of those in cellphones. They are surprisingly accurate too, usually much better than 1% out and they don't need periodic calibration. I've checked my iPhone and iPad against a calibrated and tested VOR/DME and altimter in an aeroplane and I'm amazed how good they are - certainly good / accuate enough for aviation navigation (although non-approved devices aren't actually legal for such purposes, due mainly to the reliability of the GPS signal than the accuracy of the device)

Andy
 

jon0844

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Sony Ericsson (and other devices using certain Qualcomm chipsets) can also pick up GLONASS satellites for even better accuracy.
 

Grantham

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Its also worth mentioning that 66's have three speedo readings in each cab and none of them will report the same speed. Speedo on the dash panel, speedo on the Q-Tron and speedo on the EM2000. 60's only have dash and Q-Tron speedo's. Don't sign 43's or 91's so can't comment on those though.
Same problem on every engine I've been on with more than one speed readout.

A driver with a speedometer always knows how fast he is going. A driver with several is never certain!
 

Cherry_Picker

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It may happen in the oddest of places.. a few months back I was on a Metropolitan line train leaving Harrow-o-T-H shortly before a Chiltern diesel did

As the 165 caught up the Met driver dropped the hammer. A-Stock on a good day can't half go and when a few other passengers expressed alarm I flicked on a phone GPS [usual caveat about reliability] and recorded the train accelerating to 78mph before settling down to a steady 70

(all London Transport lines have a 50mph limit but the As were designed for 75 and allegedly capable of 108 per someone I know who used to drive them)

Overtook the Chiltern rail train in full after it had got right past us...
I find that difficult to believe. The speed limit on the fast lines is 40 out of Harrow on the Hill, raising to 60 beyond North Harrow and falling back to 50 through Moor Park. I have no idea what the speed limit on the slow lines is there, but speeds of 70 - 78 seem unrealistic. Did you capture a screenshot of this on your phone at all? The stretch of the Met between Amersham and Chorleywood is 60mph too, so the claim that all London transport lines have a speed limit of 50 is inaccurate.

Its also worth mentioning that 66's have three speedo readings in each cab and none of them will report the same speed. Speedo on the dash panel, speedo on the Q-Tron and speedo on the EM2000. 60's only have dash and Q-Tron speedo's. Don't sign 43's or 91's so can't comment on those though.

67s are the same. You have to go out of your way to see the speedo on the Q-Tron and the EM2000 though so just to use the one on the dash. I know I do. I take your point about the inaccuracies of speedometers though.
 

O L Leigh

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I always book a faulty speedo as a record of the fault in case anyone gets their collar felt for speeding on any given unit. I can usually tell when one is dodgy because it seems to take an age to get up to linespeed but then braking for the first station is a problem because you're actually going faster than the gauge says you're going. It can be a frightening moment. But then I go into a "no speedo" mode where I drive the train according to lineside markers based on the speeds I expect a train to be going at any given point. This seems to work well enough and has kept me out of the gaffer's office so far.

O L Leigh
 

Legzr1

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67s are the same. You have to go out of your way to see the speedo on the Q-Tron and the EM2000 though so just to use the one on the dash. I know I do. I take your point about the inaccuracies of speedometers though.
The main speedo (dashboard) is the one that matters (and the one that should guide drivers).


The digital speedo on the EM2000 can be a nightmare on Cl 66's if it's over-reading.

It should cut power at 78-ish mph and apply train brake a little afterwards - it's annoying when some units cut power at a real 65mph and dump train brake at 70mph - try keeping to class 4 timings with those units <(

Repair book : "tested on shed,NFF" <(<(
 
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