HST's at 125.X mph

[Kromaatikse]

The 91, Mk4 stock and DVT are all rated to 140mph, but no railway line in the UK has a speed lmit that high except HS1. The 91 and DVT however do not have the required cab-signalling equipment to operate on that line, which does not have conventional colour-light signals.

The main reason why speeds above 125mph are not permitted on conventional lines is due to the difficulty of reading lineside signals at high speed. It is doable by an alert driver in good weather, and some tests were run at that speed, but it is not always good weather and drivers are not always super-alert.

There is a school of thought that building a modernised version of the 91 and Mk3/4 stock, rated for 125mph, would be a better solution to the IEP problem.

[FoggyMorning]

The 91, Mk4 stock and DVT are all rated to 140mph, but no railway line in the UK has a speed lmit that high except HS1. The 91 and DVT however do not have the required cab-signalling equipment to operate on that line, which does not have conventional colour-light signals.

The main reason why speeds above 125mph are not permitted on conventional lines is due to the difficulty of reading lineside signals at high speed. It is doable by an alert driver in good weather, and some tests were run at that speed, but it is not always good weather and drivers are not always super-alert.

There is a school of thought that building a modernised version of the 91 and Mk3/4 stock, rated for 125mph, would be a better solution to the IEP problem.

I believe part of the ECML had a part of the southern section with a 140mph speed limit when newly electrified. I believe this was reduced following the spate of late-90s rail crashes at Potters Bar etc.

[chrisiveson]

It was experimental Steve,
with flashing green for 140 mph. and was on the four track section between New England North and Stoke tunnel.
that was in the eighties and at the time, the signalling wasn't far advanced enough to detect two broken rails.
It's maybe little known, but the fastest recorded speed on the ECML was 161 mph, the prototype HST also recorded a speed of 141 mph.

Chris.

[FoggyMorning]

Thanks Chris, it seems I was misinformed

[chrisiveson]

It might have been some time later that the 140 mph running was tested especially with the later introduction of MK IV coaches.
And as far as I'm aware, the flashing green signalling is still in place. ( I'd be happy to be corrected on that though. )
The actual speed record for the P-HST was 143.2 mph. on the race track between York and Northallerton.

Chris.

// having re-checked my book on the subject, the initial tests were made with a 91 at each end as there were no MK IV DVT's at the time. ( eventually, buffered HST power cars would be used. )
Another less interesting fact, other than the HMRI decreeing 125 was to be the maximum speed without cab signalling, a fully loaded 225 or 125 trainset would not be able to actually get to 140 mph. on the climb to Stoke summit. ( those who tinker with the simulator physics could of course overide that theory. )

[holzroller]

In BR Days until around the 80's the rule book stated that drivers were allowed to exceed line speed by 3 mph to make up time. In fact most drivers of the time would learn where they could safely exceed line speed as part of their route learning, and would do so to make up time. To a large extent a blind eye was turned towards this unless the speeds were too excessive, and a driver might get a warning if he was unlucky, or a little more if he was too gung ho. HST's were fitted with the regulators as it became apparent that they were regularly being driven in excess of 130 mph on the western region soon after introduction. The regulator normally cut out power at 127/128 mph. Occasionally it didn't work, and occasionally it cut out power too low. On the modern railway as already mentioned things are very different. I am aware of two occasions in the 80's where drivers were accompanied by a p-way engineer and asked to demonstrate where they felt the line speed was too low, subsequently some speed restrictions were relaxed a little, but not all. Conversely at the time there were one or two locations where drivers would run below line speed as they felt the line speed was too high.

[Kariban]

Heh, I can vaguely remember riding a HST doing well over 130 somewhere between Didcot & Bristol not long after introduction ( being tiny I can't remember many details ). ERTMS fitting might make that a common experience again under the wires, I have no idea if they plan to fit the remaining HSTs though - I guess that depends if the B&H/B&E lines get it. The LSWR line to Exeter is also getting ERTMS and that's the main diversory route to the west country.

[chrisiveson]

My most frightening ride in a HST goes back to the days before TGS and I was returning home to York from Edinburgh.
I was right at the back of the rear coach as it was "smoking" ( not the actual coach, just passengers were allowed to smoke. ) and when we hit the curve at Dunbar I was nearly thrown from my seat.
I was reading a book so hadn't noticed where we were and was a bit shocked when the coach suddenly jolted, I was so convinced we were off the track, but there was no emergency braking and the train carried on normally all the way to York.

Chris.

[holzroller]

hmmm there was a Haymarket driver known as barmy harmy for good reason, maybe you had the privilege on that occasion. Must admit I was no slouch myself when the need arose. As a passenger I can remember doing 136 on the southern end of the ECML, regulator must have been u/s on that occasion. No opportunity for those kind of speeds up here though . HST's were fun to drive in those days.

[Inthernet]

At all events, high speed is a combination of all the elements which constitute the “system”: infrastructure (new lines designed for speeds above 250 km/h and upgraded lines for speeds up to 200 or even 220 km/h

http://www.uic.org/spip.php?article971

So the IC125 *just* qualifies as high speed. That said, it's annoying that the 125mph sections in Railworks is set as 124. I tend to ignore the 'overspeed' and tend to do 124 - 125.5 mph on those sections.

(On an unrelated note, I gave a retired driver a go in Railworks over Xmas and he found the game's Class 47 far too slow - he claims to have done 110mph driving them!)

[phill70]

(On an unrelated note, I gave a retired driver a go in Railworks over Xmas and he found the game's Class 47 far too slow - he claims to have done 110mph driving them!)

I would be absolutely staggered if that was true, most of the ones I drove strugged to hit 95.

[Kromaatikse]

The 47 could easily be tweaked to give it more power in several parts of the speed band without being at all unrealistic.

[chrisiveson]

The 47 could easily be tweaked to give it more power in several parts of the speed band without being at all unrealistic.

Are we talking simulator or the real thing though?
The 47/7 were up-rated to 100 mph. for working the Edinburgh - Glasgow PP's, and I'm fairly sure there was a little bit more on a good day.

Chris.

[Kariban]

The sim one. I've no doubt good real 47s could top 100mph if they'd had a service but I'm not too sure they're that safe to! I read a thread about 47s and speed very recently, might even have been here somewhere.

I suspect the sim one might have a rather low speed cap ( MaxSpeed ).

[salopiangrowler]

on a 125mph section the TPWS triggers at 128mph. allowing a 3mph differential incase of delay and the need to make up some lost time. ive managed to clock a HST at 143 mph between Paddington and Reading ( i think we did it around the area between Slough and Maidenhead. ) in 1992.

interestingly the Computer on a Pendolino doesnt take over control till the pendolino has reached 127.5mph which also suggests the WCMLs TPWS grates also trigger at 128 on a 125 section. ive had a few hairy moments on Weedon Curves

Which imo if a freight service is operating on the ECML and WCML and the slow lines Exceed the freight maximum of 75 mph, if they can do it some drivers would no doubt be tempted to go over that maximum as unless its built into the actual locomotive theres nothing stopping a freightliner doing full line speed on a 90mph section.