Eurostar scrapping class 373s

[phil-b259]

Possibly in the Sectional Appendix - definitely not in the 1998 Rule Book.

 

Interesting that the renewals also have flashing greens.

 

 

Cheaper to just replace the signal heads and leave everything else the same?

 

Correct!

 

The flashing aspects would have required additional relays and wiring to be fitted to lineside cabinets, including alterations to the 'standard' wiring arrangements for the control of the 4 aspect signals so to subsequently go round removing all this would be costly and provide no real benefit.

 

These 'hidden form public gaze issues' are why you sometimes get signals still lit at the exit to disconnected sidings or points that are still featured in the interlocking even though they have been removed on site with the detection strapped out to fool the interlocking they are correctly set, or why on the BML lots of cabinets still contain the wiring and relays for flashing double yellows even though BR (S) took a high level decision not to commission them back in 1984.

 

Furthermore modern signal heads (whatever their external appearance) have been specifically designed to be backwards compatible with their filament predecessors - they use the same control inputs, same supply voltages and same number of cable cores precisely so they can be a direct replacement with no alterations necessary to any existing wiring arrangements.

[jamie92208]

Correct!

 

The flashing aspects would have required additional relays and wiring to be fitted to lineside cabinets, including alterations to the 'standard' wiring arrangements for the control of the 4 aspect signals so to subsequently go round removing all this would be costly and provide no real benefit.

 

These 'hidden form public gaze issues' are why you sometimes get signals still lit at the exit to disconnected sidings or points that are still featured in the interlocking even though they have been removed on site with the detection strapped out to fool the interlocking they are correctly set, or why on the BML lots of cabinets still contain the wiring and relays for flashing double yellows even though BR (S) took a high level decision not to commission them back in 1984.

 

Furthermore modern signal heads (whatever their external appearance) have been specifically designed to be backwards compatible with their filament predecessors - they use the same control inputs, same supply voltages and same number of cable cores precisely so they can be a direct replacement with no alterations necessary to any existing wiring arrangements.

Thanks for that. I seem to remember that there was a signal at Healey Mills on a relief line that had been lifted that was still lit at least 10 years later even though there was no track at all.

 

Jamie

[Coryton]

The Rule for the flashing green aspects did make it into print as I recall, but not sure if actually made it into the Rule Book, or if it was in a Signaling / Operating notice.

Flashing Green would allow 140 mph running and Steady Green mean reduce to 125.

 

I've always been quite intrigued by the flashing green aspect concept.

 

Viewing it as a special authorisation to exceed the normal line speed, it seems to make sense, particularly if just used for high speed tests.

 

Green keeps the same meaning as before, e.g. travel at 125 mph and flashing green gives you special authorisation to go faster than normal.

 

On the other hand by allowing faster travel on a flashing green, a steady green has become a warning to slow down which it has never been before (at least not in the lifetime of any current drivers). I know that drivers route learn, but I would be concerned that there would be too great a danger of a driver forgetting they were on a section of route where they have to react to a signal being green instead of flashing green and put on the brakes.

 

Also, I don't know how AWS would handle this. If you give a warning on a green that is capable of flashing, a driver of a non 140 mph capable train will have to cancel the AWS at each green. Not good I would have thought. But the alternative is a driver at 140 mph getting a bell at a steady green when they need to start to brake for a red signal ahead.

 

An alternative would be to reverse steady and flashing green, i.e. use steady green for 140 mph where the line limit permits, and flashing green as an extra aspect. This way a green means travel at line limit/train maximum limit as it always has done, and a flashing green means slow down in a 140 mph capable train and can be ignored by everyone else. This sounds as if would also be better from an AWS point of view, but then again a 125 mph train chasing another might end up "riding the flashing greens" and thus keep getting warnings which had to be cancelled.

 

I'm sure there was a reason for not doing it this way but the only one I can think of is that there is a danger of a wrong side failure if a light fails to flash and stays on steady green. But presumably this could be detected in some way.

 

I had read that the flashing greens were only intended for test purposes - but it seems a lot of effort to go to in re-wiring the signalling just for that.

 

It also occurs to me that fitting in HST services for north of Edinburgh at 125 mph and electric services at 140 mph wouldn't have helped capacity, though when the "225" sets were introduced that was probably less of a problem than now.

 

D854_Tiger, on 09 Mar 2017 - 12:48, said:

Would any retrofit of tilt to those mk4s have included the class 91 or was the intention at 140 mph just to keep the soup off passengers' laps even if that meant sending the driver swivel eyed.

 

 

Interesting question. Tilt trains are normally multiple units so the driver gets the same treatment as the passengers.

 

In Canada they run tilting coaches with non tilting engines*. But not at any great speed - I think it's more to do with superelevation aimed at the needs of slow freight trains rather than faster passenger trains.

 

We do seem to have ended up a long way from 373s on this thread.

 

* They started out with dedicated power cars. I don't know if they tilted.

[cornish trains jez]

Perhaps we should rename this thread "ECML 91's and signalling"!

 

Joking aside, really enjoying all the interesting info so please keep it coming.

[royaloak]

.No diesels can multiple / work in push-pull mode with 91s / Mk4s (which use the TDM system)

I must have imagined all those HST sets running around with a 91 at one end and both the 91 and Power Car powering back in the late 80s/early 90s!

[royaloak]

The driver would have had a smooth tilting ride in one direction, and something much less plesent the other way!

Since when has the drivers comfort been a consideration?

[cornish trains jez]

I must have imagined all those HST sets running around with a 91 at one end and both the 91 and Power Car powering back in the late 80s/early 90s!

There are plenty of videos online with both HST and class 91 powering. Those leaving Grantham station with both on full power heading South and the climb in Stoke bank is quite impressive. Some serious horsepower there!!

[royaloak]

There are plenty of videos online with both HST and class 91 powering. Those leaving Grantham station with both on full power heading South and the climb in Stoke bank is quite impressive. Some serious horsepower there!!

Oh was there a climb up to stoke summit, I never realised!

 

A very powerful combination.

[jamie92208]

Oh was there a climb up to stoke summit, I never realised!

 

A very powerful combination.

They certainly set off from Wakefield going towards Leeds at a rate of knots. Don't the modified power cars still have the buffers that were fitted.

 

Jamie

[cornish trains jez]

Here's a great video. The first train is a south bound working and you can clearly hear the HST DVT and Class 91 powering up out of Grantham for the climb up Stoke Bank.

Edited March 9, 2017 by cornish trains jez

[cornish trains jez]

They certainly set off from Wakefield going towards Leeds at a rate of knots. Don't the modified power cars still have the buffers that were fitted.Jamie

 

Yes, all allocated to Great Central trains in their smart black with orange stripe livery.

[frobisher]

Yes, all allocated to Great Central trains in their smart black with orange stripe livery.

Apart from the NR ones of course...

[Zomboid]

Since when has the drivers comfort been a consideration?

From what I've seen of the drivers seats in modern EMUs at least, it's waaaaaaaay above passenger comfort.

 

Not saying that's wrong, the cab is a workplace after all.

[Coryton]

From what I've seen of the drivers seats in modern EMUs at least, it's waaaaaaaay above passenger comfort.

 

Not saying that's wrong, the cab is a workplace after all.

 

I think driver comfort has gone up and passenger comfort down.

 

I'm not complaining about the former, but maybe passengers also need a union to be consulted when new trains are designed?

[The Stationmaster]

I've always been quite intrigued by the flashing green aspect concept.

 

Viewing it as a special authorisation to exceed the normal line speed, it seems to make sense, particularly if just used for high speed tests.

 

Green keeps the same meaning as before, e.g. travel at 125 mph and flashing green gives you special authorisation to go faster than normal.

 

On the other hand by allowing faster travel on a flashing green, a steady green has become a warning to slow down which it has never been before (at least not in the lifetime of any current drivers). I know that drivers route learn, but I would be concerned that there would be too great a danger of a driver forgetting they were on a section of route where they have to react to a signal being green instead of flashing green and put on the brakes.

 

Also, I don't know how AWS would handle this. If you give a warning on a green that is capable of flashing, a driver of a non 140 mph capable train will have to cancel the AWS at each green. Not good I would have thought. But the alternative is a driver at 140 mph getting a bell at a steady green when they need to start to brake for a red signal ahead.

 

An alternative would be to reverse steady and flashing green, i.e. use steady green for 140 mph where the line limit permits, and flashing green as an extra aspect. This way a green means travel at line limit/train maximum limit as it always has done, and a flashing green means slow down in a 140 mph capable train and can be ignored by everyone else. This sounds as if would also be better from an AWS point of view, but then again a 125 mph train chasing another might end up "riding the flashing greens" and thus keep getting warnings which had to be cancelled.

 

I'm sure there was a reason for not doing it this way but the only one I can think of is that there is a danger of a wrong side failure if a light fails to flash and stays on steady green. But presumably this could be detected in some way.

 

I had read that the flashing greens were only intended for test purposes - but it seems a lot of effort to go to in re-wiring the signalling just for that.

 

 

 

Actually it's the right way round when you think about it because if a flashing unit fails the signal will revert to steady green - which does not actually indicate a particular speed, simply that the line is clear for at least one signal section and a train is permitted to proceed at its permitted maximum speed provided that does not exceed the line speed.  The flashing green is the only signal aspect which indicates that a train may proceed at a particular stated speed although the permitted speed can be inferred in some cases from aspects approaching a divergence.

 

The other problem was of course that AWS couldn't handle the flashing green which was part of the reason HMRI weren't happy - although everyone has reasonably happily accepted for many years that AWS can as readily apply to a signal at danger as to those showing two different levels of caution aspect (which is why TPWS has been added and why more sophisitcated systems will follow on).

[Coryton]

Actually it's the right way round when you think about it because if a flashing unit fails the signal will revert to steady green - which does not actually indicate a particular speed, simply that the line is clear for at least one signal section and a train is permitted to proceed at its permitted maximum speed provided that does not exceed the line speed.  The flashing green is the only signal aspect which indicates that a train may proceed at a particular stated speed although the permitted speed can be inferred in some cases from aspects approaching a divergence.

 

Surely on multiple aspect signalling green indicates that the line is clear for more than one signal section? And green only means that line speed can be achieved if 140 mph is thought of as being above line speed (which is a view that makes perfect sense for test running but - to me - not much sense if 140 mph running is routine).

 

Flashing green being a speed indication is one way of looking at it (and again makes sense in the context of test running), but is it the only way? Isn't it just as valid to think of it as a 5th aspect? I.e. the sequence leading up to a red signal is flashing green - green - double yellow - yellow - red. In this view green is therefore a warning to slow down for a red signal just like yellow aspects.

 

Flashing green is then no more a speed indication than green is in normal 4 aspect signalling. Flashing green indicates 140 mph only in the sense that 140 mph is the line limit and there is no need to brake for a red signal.

 

Possibly I'm missing something. Maybe it was felt that at such high speeds something more than just route learning/speed limit signs were required to indicate where a 140 mph section began and finished. 

 

But however you look at it, for a train at 140 mph a green signal means slow down and that seems wrong (and dangerous) to me from a human factors point of view apart perhaps from limited use for test trains.

 

The other problem was of course that AWS couldn't handle the flashing green which was part of the reason HMRI weren't happy - although everyone has reasonably happily accepted for many years that AWS can as readily apply to a signal at danger as to those showing two different levels of caution aspect (which is why TPWS has been added and why more sophisitcated systems will follow on).

 

But in addition to AWS now indicating stop plus three levels of caution, one of those caution levels is green. So for most of the network an AWS horn on a green signal is a failure (albeit right side) but for some signals it's correct. Would getting drivers used to cancelling the AWS warning on a green signal be a good thing? (I would argue not). Again if green and flashing green were swapped this wouldn't be a problem.

 

But as you say if you swap green and flashing green over you have a wrong side failure if the light fails to flash. I could imagine a separate circuit which monitored this and set the signal to red if the green was supposed to flash and didn't though. Are level crossing flashing red road signs monitored in some way to make sure they don't fail in a steady red state?

 

 

 

 

 

 

 

Actua

Actually it's the right way round when you think about it because if a flashing unit fails the signal will revert to steady green - which does not actually indicate a particular speed, simply that the line is clear for at least one signal section and a train is permitted to proceed at its permitted maximum speed provided that does not exceed the line speed.  The flashing green is the only signal aspect which indicates that a train may proceed at a particular stated speed although the permitted speed can be inferred in some cases from aspects approaching a divergence.

 

The other problem was of course that AWS couldn't handle the flashing green which was part of the reason HMRI weren't happy - although everyone has reasonably happily accepted for many years that AWS can as readily apply to a signal at danger as to those showing two different levels of caution aspect (which is why TPWS has been added and why more sophisitcated systems will follow on).

lly it's the right way round when you think about it because if a flashing unit fails the signal will revert to steady green - which does not actually indicate a particular speed, simply that the line is clear for at least one signal section and a train is permitted to proceed at its permitted maximum speed provided that does not exceed the line speed.  The flashing green is the only signal aspect which indicates that a train may proceed at a particular stated speed although the permitted speed can be inferred in some cases from aspects approaching a divergence.

 

The other problem was of course that AWS couldn't handle the flashing green which was part of the reason HMRI weren't happy - although everyone has reasonably happily accepted for many years that AWS can as readily apply to a signal at danger as to those showing two different levels of caution aspect (which is why TPWS has been added and why more sophisitcated systems will follow on).

 

[nightstar.train]

The Mk4 set's a heavy train by passenger standards, around 450 tons

I'll be interested to compare these figures to the new Mk5s. On the one hand they have lots of weight adding bells and whistles like at seat power and wifi, not to mention newer and presumably harsher crash worthiness standards, but on the other hand they benefit from nearly three decades of materials science and advances in engineering.

[Ken.W]

I'll be interested to compare these figures to the new Mk5s. On the one hand they have lots of weight adding bells and whistles like at seat power and wifi, not to mention newer and presumably harsher crash worthiness standards, but on the other hand they benefit from nearly three decades of materials science and advances in engineering.

And that they'll only be 5 coach sets

[Ken.W]

Surely on multiple aspect signalling green indicates that the line is clear for more than one signal section? And green only means that line speed can be achieved if 140 mph is thought of as being above line speed (which is a view that makes perfect sense for test running but - to me - not much sense if 140 mph running is routine).

 

Flashing green being a speed indication is one way of looking at it (and again makes sense in the context of test running), but is it the only way? Isn't it just as valid to think of it as a 5th aspect? I.e. the sequence leading up to a red signal is flashing green - green - double yellow - yellow - red. In this view green is therefore a warning to slow down for a red signal just like yellow aspects.

 

Flashing green is then no more a speed indication than green is in normal 4 aspect signalling. Flashing green indicates 140 mph only in the sense that 140 mph is the line limit and there is no need to brake for a red signal.

 

Possibly I'm missing something. Maybe it was felt that at such high speeds something more than just route learning/speed limit signs were required to indicate where a 140 mph section began and finished. 

 

But however you look at it, for a train at 140 mph a green signal means slow down and that seems wrong (and dangerous) to me from a human factors point of view apart perhaps from limited use for test trains.

 

 

But in addition to AWS now indicating stop plus three levels of caution, one of those caution levels is green. So for most of the network an AWS horn on a green signal is a failure (albeit right side) but for some signals it's correct. Would getting drivers used to cancelling the AWS warning on a green signal be a good thing? (I would argue not). Again if green and flashing green were swapped this wouldn't be a problem.

 

But as you say if you swap green and flashing green over you have a wrong side failure if the light fails to flash. I could imagine a separate circuit which monitored this and set the signal to red if the green was supposed to flash and didn't though. Are level crossing flashing red road signs monitored in some way to make sure they don't fail in a steady red state?

The (steady) Green aspect simply means 'line clear' (anywhere), and allows a train to proceed up to it's permitted speed within the linespeed, the number of sections ahead that's clear depends on the signal aspects in use, and in some locations this can be just one section - where there's long sections and the next signal ahead's a repeater (C.L. equivelent of a distant), so there's no change to the normal meaning of the green aspect.

The flashing Green was designed to give, in effect, a fifth aspect to give trains traveling at up to 140 an extra signal section for normal service breaking, and allowing an increase above the normal speed of the train. The section of line was, at the time, actually signed for 140 linespeed (with 135 restrictions on some of the curves!).

As Mike pointed out, with the flashing aspect allowing enhanced speed, failure of the flasher unit simply fail-safes the signal to steady green, and so has no effect on other services - only a 140 mph train would need to slow for a section instead of having to stop everything. The system is, as I said earlier, still operational - well, mostly, occasional flasher units have failed but everything just carries on as normal with no urgency to replace them.

 

As far as the AWS is concerned, this operates normally with the bell at a Green not a warning.

 

It should be remembered though, that the 140 mph running on Flashing Greens was only ever authorised for test running, and never became routine. As such the Drivers (and there would still have been two for over 110 mph running then) would have been operating under special instructions and, probably, also accompanied by an inspector. It was later decided that a fifth aspect for higher speed running was unsatisfactory and that full in-cab signaling would be required for any further speed increases.

[Suzie]

Flashing green is quite normal in North America for indicating higher speed than green that requires cab signalling on Amtrak's Northeast Corridor, and it is quite normal to upgrade the speed of a signal aspect by flashing it in North American signalling. There are a few examples of adding speed aspects to signal systems that are primarily route signalling systems like in the UK. There should be plenty of examples out there to learn from as to whether it is a good idea or not.

[The Stationmaster]

The (steady) Green aspect simply means 'line clear' (anywhere), and allows a train to proceed up to it's permitted speed within the linespeed, the number of sections ahead that's clear depends on the signal aspects in use, and in some locations this can be just one section - where there's long sections and the next signal ahead's a repeater (C.L. equivelent of a distant), so there's no change to the normal meaning of the green aspect.

The flashing Green was designed to give, in effect, a fifth aspect to give trains traveling at up to 140 an extra signal section for normal service breaking, and allowing an increase above the normal speed of the train. The section of line was, at the time, actually signed for 140 linespeed (with 135 restrictions on some of the curves!).

As Mike pointed out, with the flashing aspect allowing enhanced speed, failure of the flasher unit simply fail-safes the signal to steady green, and so has no effect on other services - only a 140 mph train would need to slow for a section instead of having to stop everything. The system is, as I said earlier, still operational - well, mostly, occasional flasher units have failed but everything just carries on as normal with no urgency to replace them.

 

As far as the AWS is concerned, this operates normally with the bell at a Green not a warning.

 

It should be remembered though, that the 140 mph running on Flashing Greens was only ever authorised for test running, and never became routine. As such the Drivers (and there would still have been two for over 110 mph running then) would have been operating under special instructions and, probably, also accompanied by an inspector. It was later decided that a fifth aspect for higher speed running was unsatisfactory and that full in-cab signaling would be required for any further speed increases.

 

The other point is that it might not necessarily mean the line is clear for an extra signal section - that depends entirely on the signal spacing (which might not be consistent) and the gradient - which of course affects the stopping distance.  Hence the specific meaning of the flashing green aspect.

[RJS1977]

As regards the question raised about 58s/60s/90s being 'retired' with decades of potential service still in them, as I understand things:

 

1) At the time that the 66s were ordered, the 58s were approaching a major mid-life refit. At that point ordering a further 50 66s may well have worked out cheaper in the long run than refurbishing a relatively small, non-standard class of locos.

 

2) Whilst the diesels may be running for considerable distances under the wires, unless the entire journey is on electrified lines (including the loading/unloading points), then a diesel would be needed for at least part of the journey. I can see how economically it could make more sense to run a diesel under wires for most of its journey than have to use two (or even three) different locos and associated crews.

[Ron Ron Ron]

 

 

 

 

 

 

That must have been one of my more memorable quotes then........?

 

 

 

.

[The Stationmaster]

Ignore previous post - posted in error and cannot figure out how to delete!

 

You can click on 'Hide' - which not delete the post but will, hmm, 'hide' it from view in the thread.

[flapland]

Mmm, a couple of my posts have dissapered related to the journey from St Pancras to the Kingsbury scrap yard. 

 

Ignore as they are over on the questions forum  

Edited March 12, 2017 by flapland