HST future operations

[5BarVT]

9 hours ago, roythebus1 said:

exceeding 60mph

Don’t forget that Scotland had the last remaining 100mph line signalled by semaphores.

Paul.

[The Stationmaster]

3 hours ago, 5BarVT said:

Don’t forget that Scotland had the last remaining 100mph line signalled by semaphores.

Paul.

Now that is interesting in view of the fact that at one time, when HSTs were first being introduced,  the Railway Inspectorate required any BR high speed (i.e. 100 mph or higher) line to have 3 aspect signalling as a minimum.  Hence lots of fairly new 2 aspect signalling on the WR had to be converted to 3 aspect for the introduction of HSTs.

[hexagon789]

4 hours ago, The Stationmaster said:

Now that is interesting in view of the fact that at one time, when HSTs were first being introduced,  the Railway Inspectorate required any BR high speed (i.e. 100 mph or higher) line to have 3 aspect signalling as a minimum.  Hence lots of fairly new 2 aspect signalling on the WR had to be converted to 3 aspect for the introduction of HSTs.

To the best of my knowledge, there is 110mph on 2-aspect on the northern (ie Berwick-Edinburgh) section of the ECML, places on the ECML and GWML with 125mph on 3-aspect and a few surviving places in Scotland with and without HST differentials of 95-100mph on colour light distants and semaphore home signals.

[westie7]

22 minutes ago, hexagon789 said:

To the best of my knowledge, there is 110mph on 2-aspect on the northern (ie Berwick-Edinburgh) section of the ECML, places on the ECML and GWML with 125mph on 3-aspect and a few surviving places in Scotland with and without HST differentials of 95-100mph on colour light distants and semaphore home signals.

 

Fordoun to Marykirk through Laurencekirk, up and down. 100

 

Broughty Ferry to Elliot through Carnoustie, down 100

 

Great fun coming round the corner hitting a single yellow distant at 100

Edited August 2, 2022 by westie7

[hexagon789]

33 minutes ago, westie7 said:

 

Fordoun to Marykirk through Laurencekirk, up and down. 100

 

Broughty Ferry to Elliot through Carnoustie, down 100

 

Great fun coming round the corner hitting a single yellow distant at 100

As a former driver once described running 100mph on tread braked stock encountering yellows:

 

"Shut off, full service and no fannying about."

Edited August 2, 2022 by hexagon789

[westie7]

26 minutes ago, hexagon789 said:

As a former driver once described running 100mph on tread braked stock encountering yellows:

 

"Shut off, full service and no fannying about."

Bad enough on discs, especially if the discs are sh1t, as per usual 

[hexagon789]

2 hours ago, westie7 said:

Bad enough on discs, especially if the discs are sh1t, as per usual 

I don't know how true it is, but I had the Class 170 3-step brake described to me as:

 

"1. Naethin'

2. Bit less than naethin'

3. Everybody joins you in the cab"

Edited August 2, 2022 by hexagon789

[russ p]

2 hours ago, hexagon789 said:

I don't know how true it is, but I had the Class 170 3-step brake described to me as:

 

"1. Naethin'

2. Bit less than naethin'

3. Everybody joins you in the cab"

 

170s can vary with brake rates. The central ones had enhanced brake pressures 

When central got the Midland mainline ones had few interesting moments as step  3 on an MML one wasn't far off step 2 on a central one

[Michael Hodgson]

On 29/07/2022 at 10:58, The Stationmaster said:

I think lots of contemporary cabs are like death traps and I would hate to be the Driver in some of them in the event of a collision at any sort of speed.

Aye, but they all have better crumple zones than a giant tortoise in the four-foot!

https://www.ndtv.com/world-news/escaped-giant-tortoise-halts-trains-for-two-hours-in-uk-3217791

[westie7]

3 hours ago, hexagon789 said:

I don't know how true it is, but I had the Class 170 3-step brake described to me as:

 

"1. Naethin'

2. Bit less than naethin'

3. Everybody joins you in the cab"

 

Total fantasy... Only ever failed one

[hexagon789]

10 hours ago, westie7 said:

 

Total fantasy... Only ever failed one

So 170s brake as you would expect with a 3-step.

 

I thought they must do, because otherwise - firstly that would negate one of the basic ideas with a 3-step brake, giving consistent graduation; secondly, it seemed like a significant issue with regards to safely controlling the train.

Edited August 3, 2022 by hexagon789

[The Stationmaster]

17 hours ago, hexagon789 said:

As a former driver once described running 100mph on tread braked stock encountering yellows:

 

"Shut off, full service and no fannying about."

Depending on the distance you have available and other factors - especially with tread braked stock where brake performance varied depending on the age of the brake blocks.  Part of the problem with British signalling, particularly in some 1960s installations, is the variation in the distance been the caution aspects and the red aspect (and not just for gradient reasons).  This could lead to some very different approaches to driving on restricted aspects with parts of the Southern having trains running at line speed on double yellows while keeping a good lookout for the single one (although it is a practice which did lead to a poorer SPAD rate and was condemned in consequence).

 

On the 1960s signalling on some parts of the WR - which was installed for lower maximum speeds than 100mph - you could react very differently to certain double yellows when running at 95mph depending on which signal it was.  In some cases you simply shut off and kept a very careful watch for the next signal (because it gave you service braking distance from when you sighted it).  While at others you shut off and put the brake in depending on the feel of the brakes on the stock (a set which had just been re-blocked was normally the worst followed by one where the blocks were very well worn).  So if you had a train with new blocks instead of just shutting off at a particular signal you also got the brakes rubbing on the train to help get the effect you wanted when you put the brake in.

[hexagon789]

1 hour ago, The Stationmaster said:

Depending on the distance you have available and other factors - especially with tread braked stock where brake performance varied depending on the age of the brake blocks.  Part of the problem with British signalling, particularly in some 1960s installations, is the variation in the distance been the caution aspects and the red aspect (and not just for gradient reasons).  This could lead to some very different approaches to driving on restricted aspects with parts of the Southern having trains running at line speed on double yellows while keeping a good lookout for the single one (although it is a practice which did lead to a poorer SPAD rate and was condemned in consequence).

 

On the 1960s signalling on some parts of the WR - which was installed for lower maximum speeds than 100mph - you could react very differently to certain double yellows when running at 95mph depending on which signal it was.  In some cases you simply shut off and kept a very careful watch for the next signal (because it gave you service braking distance from when you sighted it).  While at others you shut off and put the brake in depending on the feel of the brakes on the stock (a set which had just been re-blocked was normally the worst followed by one where the blocks were very well worn).  So if you had a train with new blocks instead of just shutting off at a particular signal you also got the brakes rubbing on the train to help get the effect you wanted when you put the brake in.

I read that when Eurostar commencing running, the behaviour of French drivers in relation to cautionary signals was causing some issues.

 

They were trained to put the brake in immediately on sighting a cautionary signal, because braking distances on the SNCF are far more consistent than in the UK, so a 50% application is needed immediately on sighting a yellow to bring the speed down properly.

 

Consequently they were running on consecutive double yellows in southern England at about 30mph or less, causing late running. The British drivers meanwhile were running at about 50-70 depending on the location.

 

I can't remember if it was in a Railway Magazine issue of the period or another publication that described this.

[Fat Controller]

5 minutes ago, hexagon789 said:

I read that when Eurostar commencing running, the behaviour of French drivers in relation to cautionary signals was causing some issues.

 

They were trained to put the brake in immediately on sighting a cautionary signal, because braking distances on the SNCF are far more consistent than in the UK, so a 50% application is needed immediately on sighting a yellow to bring the speed down properly.

 

Consequently they were running on consecutive double yellows in southern England at about 30mph or less, causing late running. The British drivers meanwhile were running at about 50-70 depending on the location.

 

I can't remember if it was in a Railway Magazine issue of the period or another publication that described this.

There was also an issue in the Tunnel; the TVM on E* has 80 kph, followed by 160 kph. Eurotunnel's own trains have intermediate 'steps' of 100 and 140. Thus a E*, following a Shuttle, would catch up with it, then reduce speed to 80kph. The Shuttle would move away from the E*, and the same would happen again. Eventually, someone cottoned on, and the signallers would advise the E* drivers that they were following a (slightly) slower train. The E* drivers would then regulate their speed accordingly. A similar thing would happen if a Shuttle was behind a National Railways' freight.

[hexagon789]

1 hour ago, Fat Controller said:

There was also an issue in the Tunnel; the TVM on E* has 80 kph, followed by 160 kph. Eurotunnel's own trains have intermediate 'steps' of 100 and 140. Thus a E*, following a Shuttle, would catch up with it, then reduce speed to 80kph. The Shuttle would move away from the E*, and the same would happen again. Eventually, someone cottoned on, and the signallers would advise the E* drivers that they were following a (slightly) slower train. The E* drivers would then regulate their speed accordingly. A similar thing would happen if a Shuttle was behind a National Railways' freight.

That's stirred up another recollection. This was definitely from an article in the Railway Magazine, describing a cab run on Eurostar - the signaller advised the E* driver they were following a Shuttle and the E* driver held speed at 137km/h through the tunnel - just below the Shuttle maximum.

[The Stationmaster]

On 03/08/2022 at 13:24, hexagon789 said:

I read that when Eurostar commencing running, the behaviour of French drivers in relation to cautionary signals was causing some issues.

 

They were trained to put the brake in immediately on sighting a cautionary signal, because braking distances on the SNCF are far more consistent than in the UK, so a 50% application is needed immediately on sighting a yellow to bring the speed down properly.

 

Consequently they were running on consecutive double yellows in southern England at about 30mph or less, causing late running. The British drivers meanwhile were running at about 50-70 depending on the location.

 

I can't remember if it was in a Railway Magazine issue of the period or another publication that described this.

They would only run on consecutive double yellows if they were running before time as the trains were all timed to run on greens and usually even the sighting distance would have meant they didn't see a double yellow (rather different via Maidstone as I explained above.  But if the train was timed in the second path of a flight through the Tunnel and the first path in that flight was empty and the train had entered the Tunnel a little early it would inevitably be running on double yellows somewhere between Ashford and Tonbridge because it was running before time.

 

My normal train back from Paris was the 17.10 and it inevitably made up time by the method outlined above so it would be on double yellows as it neared Tonbridge (UK Driver so speed was usually balance).  What then happened was that the Railtrack signalling folk applied a bit of good old fashioned regulating and gave the Paris train at run at Tonbridge to overtake the train by then standing in the platform - so the Paris then made up a bit more time while the one it had passed at Tonbridge had a clear run and was soon back on time.  Alas the Trackie 'management' took a dim view of this but craftily retaliated by applying the late running penalty clause charge to the early running Paris train (£100 per minute) and very rapidly clocked up a four figure sum before presenting the invoice - much 'debate' among access managers duly ensued and in the end the Trackies relented before they were taken to the relevant Access sub-committee (of which I was a member, although I couldn't have heard that case of course).  And the Paris train ceased to arrive quite as early as it had been at Waterloo

[Michael Hodgson]

On 03/08/2022 at 12:02, The Stationmaster said:

 

On the 1960s signalling on some parts of the WR - which was installed for lower maximum speeds than 100mph - you could react very differently to certain double yellows when running at 95mph depending on which signal it was.  In some cases you simply shut off and kept a very careful watch for the next signal (because it gave you service braking distance from when you sighted it).  While at others you shut off and put the brake in depending on the feel of the brakes on the stock (a set which had just been re-blocked was normally the worst followed by one where the blocks were very well worn).  So if you had a train with new blocks instead of just shutting off at a particular signal you also got the brakes rubbing on the train to help get the effect you wanted when you put the brake in.

 

Yes, route knowledge comes into it in the UK - on mainland Europe you are more likely to have signals which tell you what speed to drive at - which presumably means their drivers do not need such detailed knowledge of the route.

 

On parts of the GE the signal spacing wasn't sufficient to give adequate braking, so you used to have "aspect sequences", where you might enocunter two or three YY aspects before the Y preceding the Red; or to put it another way, if you had green at certain singals, you knew the red was had to be further away than the usual next but two, an approach now deprecated.

 

I think 100mph trains (suburban sets) on the some parts of the ECML can treat YY as line speed, and only start braking on sighting single yellow. 

 

And on the experimental scheme with flashing greens which were originally intended for speeds above 125, if was only those higher speed trains which had to treat the flashing green as a cautionary aspect - ordinary 125 trains could treat them as green.

[phil-b259]

2 hours ago, Michael Hodgson said:

 

And on the experimental scheme with flashing greens which were originally intended for speeds above 125, if was only those higher speed trains which had to treat the flashing green as a cautionary aspect - ordinary 125 trains could treat them as green.

 

Other way round - if the flasher failed then a driver could end up believing he could go faster than permitted and run out of braking distance!

 

The flashing green indicated 140mph was possible - if the green was steady then a 125mph max (as per the rest of the UK - where infrastructure allows) applied.

 

2 hours ago, Michael Hodgson said:

 

I think 100mph trains (suburban sets) on the some parts of the ECML can treat YY as line speed, and only start braking on sighting single yellow. 

 

 

Correct - and as the slow lines usually had a 100mph limit versus 125mph on the fasts, signals would be installed as with 3 aspect types on the slows and 4 aspects on the fast.

 

Edited August 5, 2022 by phil-b259

[Michael Hodgson]

15 minutes ago, phil-b259 said:

 

Other way round - if the flasher failed then a driver could end up believing he could go faster than permitted and run out of braking distance!

 

 

Yes indeed, this hot weather is fogging my brain!

 

The signals are still there, but all trains now treat green and flashing green the same as it was decided that cab signalling was necessary for higher speeds as lineside signals weren't good enough above 125.

[hexagon789]

2 hours ago, Michael Hodgson said:

I think 100mph trains (suburban sets) on the some parts of the ECML can treat YY as line speed, and only start braking on sighting single yellow. 

It may be theoretically feasible but I would suspect modern defensive driving policies mean that isn't the case in practice. 

 

[The Stationmaster]

16 hours ago, Michael Hodgson said:

 

Yes, route knowledge comes into it in the UK - on mainland Europe you are more likely to have signals which tell you what speed to drive at - which presumably means their drivers do not need such detailed knowledge of the route.

 

On parts of the GE the signal spacing wasn't sufficient to give adequate braking, so you used to have "aspect sequences", where you might enocunter two or three YY aspects before the Y preceding the Red; or to put it another way, if you had green at certain singals, you knew the red was had to be further away than the usual next but two, an approach now deprecated.

 

I think 100mph trains (suburban sets) on the some parts of the ECML can treat YY as line speed, and only start braking on sighting single yellow. 

 

And on the experimental scheme with flashing greens which were originally intended for speeds above 125, if was only those higher speed trains which had to treat the flashing green as a cautionary aspect - ordinary 125 trains could treat them as green.

Repetitional double yellows were banned in new work a long way back, possibly as early as the 1980s, because they were regarded as potentially misleading and dangerous.  I don't know if there was ever a campaign removal where signalling was not being renewed but I know of one on the WR where the repetitional aspect was removed.   I doubt if any still exist although there is still some 1960s/70s MAS about so it is a possibility.

[Michael Hodgson]

6 hours ago, The Stationmaster said:

Repetitional double yellows were banned in new work a long way back, possibly as early as the 1980s, because they were regarded as potentially misleading and dangerous.  I don't know if there was ever a campaign removal where signalling was not being renewed but I know of one on the WR where the repetitional aspect was removed.   I doubt if any still exist although there is still some 1960s/70s MAS about so it is a possibility.

There were still some in use until the "Warm sceheme" (West Anglia Route Modernisation) a few years ago  - in the Hackney Downs area.

[phil-b259]

On 05/08/2022 at 21:00, hexagon789 said:

It may be theoretically feasible but I would suspect modern defensive driving policies mean that isn't the case in practice. 

 

 

Quite obviously a train running at 100mph needs less braking distance than one running at 125mph

 

As such it could well be the case that if the 4 aspect signalling is based round 125mph being the maximum speed under green signals, a train running at 100mph may well be able to avoid braking at double yellow aspect and keep funning at 100mph till a single yellow is sighted**.

 

The downside of this is the continued use of the AWS system (which is frankly pretty useless in a 4 aspect environment giving exactly the same cautionary indication for double yellow, single yellow and red) as there is a significant risk that drivers running on double yellows may drop into 'autopilot' and fail to slow when confronted by a single yellow or stop at a red aspect! 

 

The spectre of the Purley accident*  thus looms large over any manager contemplating a 'treat double yellow as green' strategy (even though it may be perfectly reasonable from a braking distance point of view) and consequently they will not allow anything other than double yellow = start slowing driving strategy.

 

 

* https://en.wikipedia.org/wiki/Purley_station_rail_crash

 

** note - on sections of the ECML where the slows are 100mph max but the fasts are 125mph max, the slows get 3 aspect signalling but the fasts get 4 aspects - with fast and slow signals being located slap bang next to each other. This does suggest that a train running at 100mph on the fasts can indeed treat a double yellow as if it were a green as if it were running on the slows the signals would be incapable of showing a double yellow anyway.

[russ p]

Worst place I've come across for repeated double yellows is on the Electric lines between  Stratford and Shenfield,  you can get three double yellow signals , a single then red 

This is to facilitate the running of trains other than EMUs over the lines with very closely spaced signals 

[phil-b259]

8 hours ago, russ p said:

Worst place I've come across for repeated double yellows is on the Electric lines between  Stratford and Shenfield,  you can get three double yellow signals , a single then red 

This is to facilitate the running of trains other than EMUs over the lines with very closely spaced signals 

 

It was often said that the whole Southern region peak time timetable relied on trains running on successive double yellows within the grater London area.

 

That was a factor in the Southern Region rejecting BR AWS for so long and pushing for research into better alternatives - research which eventually lead to the CAWS used in the ROI.