First ETCS train operates on the East Coast Mainline

[MarkyT]

ETCS with conventional signal overlays is capable of subdividing lights-on-sticks signal blocks into shorter logical ones.
Thanks to software driven interlocking, it is practical to provide the complex logic necessary.

A fitted train can follow a non-fitted one more closely, taking advantage of the shorter intermediate ETCS blocks, but clearly a non-fitted train cannot get closer to the train in front than allowed by the longer signal blocks, whether or not the forward train is equipped with working ETCS. This principle was first established in the Thameslink core, where some of the ETCS blocks are as short as 70m in length.

 

[gravitystorm]

Not in service yet, still in the testing phase and turned off between tests

I hope the testing isn't too prolonged. Given it's the 5th ETCS deployment in the UK, I hope most of the kinks have been ironed out already, and the deployment teams have a well-worn process.

By my reckoning, this also is the UK's first ETCS rollout where there are already fully-equipped trains with fully-ETCS-trained and experienced drivers, who are using ETCS elsewhere during the same diagrams. So while it will all be fresh and new (and require lots of training) for some drivers and traction (e.g. LNER) it could go into use pretty quickly for the already-equipped-and-experienced groups (e.g. Thameslink core).

That's just my view from the outside though, I'd be interested to hear if it's more complicated than it appears!

 

[St. Paddy]

I hope the testing isn't too prolonged. Given it's the 5th ETCS deployment in the UK, I hope most of the kinks have been ironed out already, and the deployment teams have a well-worn process.

By my reckoning, this also is the UK's first ETCS rollout where there are already fully-equipped trains with fully-ETCS-trained and experienced drivers, who are using ETCS elsewhere during the same diagrams. So while it will all be fresh and new (and require lots of training) for some drivers and traction (e.g. LNER) it could go into use pretty quickly for the already-equipped-and-experienced groups (e.g. Thameslink core).

That's just my view from the outside though, I'd be interested to hear if it's more complicated than it appears!

Only just over half of Thameslink Drivers are trained and Hitchin, Hornsey Inners and Welwyn on the GN. Further training is needed for those Drivers for yard working which is not needed on the NCL. Kings Cross, Hornsey outer, Cambridge, Peterborough and Kings Lynn also need training and then of course all the other Tocs and Focs that use the ECML. Also, not all trains are equipped yet either. A huge workload

 

[Bald Rick]

By my reckoning, this also is the UK's first ETCS rollout where there are already fully-equipped trains with fully-ETCS-trained and experienced drivers, who are using ETCS elsewhere during the same diagrams. So while it will all be fresh and new (and require lots of training) for some drivers and traction (e.g. LNER) it could go into use pretty quickly for the already-equipped-and-experienced groups (e.g. Thameslink core).

second deployment where drivers who were already using ETCS elsewhere. The first was on the GWML.

 

[gravitystorm]

second deployment where drivers who were already using ETCS elsewhere. The first was on the GWML.

Oh, I've got my facts wrong then! I thought the only deployment on the GWML was in the Heathrow tunnels, and neither Heathrow Express nor the Elizabeth line use ETCS elsewhere (CBTC in the Crossrail Core). Which deployment or service did I forget?

 

[MrJeeves]

Oh, I've got my facts wrong then! I thought the only deployment on the GWML was in the Heathrow tunnels, and neither Heathrow Express nor the Elizabeth line use ETCS elsewhere (CBTC in the Crossrail Core). Which deployment or service did I forget?

ETCS is in operation between Ealing Broadway and Hayes & Harlington as an overlay, as well as the Heathrow Tunnels, I believe.

 

[Meerkat]

Trains fitted with ETCS can use the virtual blocks while the signals remain for trains not fitted with ETCS. Hence it's 'Level 2 Overlay' rather than Level 1 (which does require fixed signals). The capacity gains are obviously restricted if a mix of trains is operating.

So ETCS trains can pass red signals, or do the signals work differently for ETCS vs non-ETCS trains - showing a green which doesn’t mean it’s clear to the next signal, just to the next virtual block?

 

[Bald Rick]

So ETCS trains can pass red signals, or do the signals work differently for ETCS vs non-ETCS trains - showing a green which doesn’t mean it’s clear to the next signal, just to the next virtual block?

They can go past red signals.

 

[JN114]

They can go past red signals.

Is that really the case?

As far as I can see, Thameslink core, if a movement authority is issued to an intermediate block marker; and the approaching train is confirmed in ETCS, then the signal shows single yellow; even if the full length block section is still partially occupied.

 

[St. Paddy]

They can go past red signals.

Certainly can’t on the NCL!

 

[notverydeep]

Certainly can’t on the NCL!

Presumably ETCS as installed on the NCL does not use LU style ‘lunar white’ (Central line) or blue (Victoria line) signal aspects for this purpose? I haven’t seen either on the Thameslink core…

 

[D365]

Presumably ETCS as installed on the NCL does not use LU style ‘lunar white’ (Central line) or blue (Victoria line) signal aspects for this purpose? I haven’t seen either on the Thameslink core…

No. This isn’t a feature of ETCS. Conventional signals are either overlaid, or [in most cases going forward] removed with time.

 

[St. Paddy]

Presumably ETCS as installed on the NCL does not use LU style ‘lunar white’ (Central line) or blue (Victoria line) signal aspects for this purpose? I haven’t seen either on the Thameslink core…

Correct

 

[Bald Rick]

Is that really the case?

As far as I can see, Thameslink core, if a movement authority is issued to an intermediate block marker; and the approaching train is confirmed in ETCS, then the signal shows single yellow; even if the full length block section is still partially occupied.

Certainly can’t on the NCL!

My apologies, I was relying on my memory, which is evidently defective. (Not for the first time). I remember a long debate at the time ETCS was beign specified in the TL core about which was preferable - trains passing a red signal with MA, or having a simhle yellow displayed withiut the full block to the next signal and overlap free. I could have sworn it came down to passing a red signal, but evidently not.

On the Moorgate line it becomes a moot point from 17 May !

 

[Belperpete]

The big issue with a driver receiving information from both trackside signals and cab display is what happens when the two give differing information.

The most important case of course is when one is telling the driver to stop and the other is telling him that he can proceed. For example, if the signaller "pulls the button" to stop a train, it may take differing times for that to reach the lineside signals and cab display. In an emergency, you want the driver to react to the first that tells him to stop. So I can see why the idea of allowing drivers to ignore red aspects was not taken up.

However, you also need to consider how the driver should react if the two are in effect giving radically different speed info, eg if the lineside signal is displaying single yellow but the cab display is telling him that he can go full throttle.

Where ETCS is overlaid on conventional signalling, then the movement authorities should align with the existing signalling, as with the GW overlay. However, the problems come where the ETCS provides additional capacity than the conventional signalling, as on Thameslink, as the ETCS may permit trains to do things that the conventional signalling won't, so inherently the two will not align. HMRI in particular were very opposed to drivers being given conflicting information. Which is why in the past conventional wisdom was to display a special "cab signalling" aspect.

However, even with overlay ETCS, the conventional signalling will behave differently for trains running under ETCS control. For example, there is no need for approach control of junction signals for diverging routes, as the ETCS will supervise the train speed for the junction. So if the signalling knows that the approaching train is running under ETCS, it will bypass the usual approach controls and allow the signal to clear earlier than it would for a traditional train. The idea of allowing the conventional signalling to display a yellow aspect when it knows that an approaching train is running under ETCS, when it would usually show red, seems to be just an extension of this concept.

 

[St. Paddy]

The big issue with a driver receiving information from both trackside signals and cab display is what happens when the two give differing information.

The most important case of course is when one is telling the driver to stop and the other is telling him that he can proceed. For example, if the signaller "pulls the button" to stop a train, it may take differing times for that to reach the lineside signals and cab display. In an emergency, you want the driver to react to the first that tells him to stop. So I can see why the idea of allowing drivers to ignore red aspects was not taken up.

However, you also need to consider how the driver should react if the two are in effect giving radically different speed info, eg if the lineside signal is displaying single yellow but the cab display is telling him that he can go full throttle.

Where ETCS is overlaid on conventional signalling, then the movement authorities should align with the existing signalling, as with the GW overlay. However, the problems come where the ETCS provides additional capacity than the conventional signalling, as on Thameslink, as the ETCS may permit trains to do things that the conventional signalling won't, so inherently the two will not align. HMRI in particular were very opposed to drivers being given conflicting information. Which is why in the past conventional wisdom was to display a special "cab signalling" aspect.

However, even with overlay ETCS, the conventional signalling will behave differently for trains running under ETCS control. For example, there is no need for approach control of junction signals for diverging routes, as the ETCS will supervise the train speed for the junction. So if the signalling knows that the approaching train is running under ETCS, it will bypass the usual approach controls and allow the signal to clear earlier than it would for a traditional train. The idea of allowing the conventional signalling to display a yellow aspect when it knows that an approaching train is running under ETCS, when it would usually show red, seems to be just an extension of this concept.

Firstly, on the ECML, the overlay is temporary until all necessary Drivers have been trained. One of the underlying principles we were taught as Drivers on the GN was that you must have a movement authority and a proceed aspect on the signal so I will be interested to see how they implement the Hitchin- Welwyn section while training takes place. Regarding different authority between signals and ETCS, you should always obey the most restrictive although it should never happen.

Regarding diverging junctions, I suspect that as the signal which is approach controlled remains at danger until you reach a certain point and then clears for the junction, so the ETCS will only give you a movement authority as far as the junction signal until it clears. Once the signals are removed, you will receive authority straight through the junction with the necessary speed reduction at the junction.

Of course, all this is an educated guess and we’ll probably have to wait until next year to find out.

 

[JN114]

Regarding diverging junctions, I suspect that as the signal which is approach controlled remains at danger until you reach a certain point and then clears for the junction, so the ETCS will only give you a movement authority as far as the junction signal until it clears. Once the signals are removed, you will receive authority straight through the junction with the necessary speed reduction at the junction.

On the GWML, if an approaching train is confirmed running under ETCS level 2, then approach control is bypassed and the signal clears immediately to the least restrictive aspect available; and the end of authority correspondingly extends. ETCS then gives a hook speed based on needing to slow down for the crossover/whatever then whatever is appropriate beyond that.

For example

Going into Hayes bay platform is normally approach control from red for unfitted trains.

For an ETCS fitted train, the system sees that the approaching train is running under L2, and instead of waiting for certain axle counter section(s) to occupy it will clear the signal to single yellow straight away.

 

[MarkyT]

On metro systems with CBTC, there are sometimes short-range signals at platform ends showing a special aspect (perhaps a different colour) for when cab signals and (where provided) ATO applies. They often revert to red while platform screen doors are open. I think free yellow as the lowest commonly used proceed aspect makes sense in UK for mainline ETCS overlays. There's much cost and no benefit in adding extra lamps or colour combinations to hundreds of signals on the ECML that are intended to be removed eventually. Routinely passing many successive reds en route while in ETCS mode risks desensitisation to the meaning of the danger aspect.

Edit: I note the EL has small doors closed indicators.

 

[St. Paddy]

On the GWML, if an approaching train is confirmed running under ETCS level 2, then approach control is bypassed and the signal clears immediately to the least restrictive aspect available; and the end of authority correspondingly extends. ETCS then gives a hook speed based on needing to slow down for the crossover/whatever then whatever is appropriate beyond that.

For example

Going into Hayes bay platform is normally approach control from red for unfitted trains.

For an ETCS fitted train, the system sees that the approaching train is running under L2, and instead of waiting for certain axle counter section(s) to occupy it will clear the signal to single yellow straight away.

Fascinating to hear. I look forward to seeing that, probably not until next year though

 

[choochoochoo]

The block marker on the down at Drayton park is beyond the platform end signal.

I asked a trainer if the signal is red and a driver is operating in level 2 and has MA to that block marker, but for some reason stops beyond the red, is that a Spad ?. They said yes, even though the driver is not driving to the lights on sticks. I thought that odd.

(Assuming it is ECS so stopping for platform duties isn’t required. The train isn’t gapped as the rear shoes should be on the third rail still so no other operational incident has occurred)

 

[Tim M]

Much of this discussion is fascinating. It might be worth remembering that all this will have been though through:

• During the pan European development of ERTMs (incorporating ETCS and GSM-R) Some twenty plus years ago. The U.K. was represented on the steering committees by what is now Network Rail and certainly Westinghouse (former colleagues) and possibly Alstom, others may confirm.
• As part of writing augmented Rule Books (and many other documents) for each country implementing the system.
• By incorporating specific country specific variables as permitted in the base ETCS product.

As an example of a country specific requirement, the Norwegians had a problem with rollback. Common with most if not all ATP systems, if a train starts to roll back the Emergency Brake relay drops and the train stops, usually in less than one wheel rotation. In Norway trains sometimes need to roll back in order to charge snow drifts, I guess this applies to other countries with the similar weather conditions. I don’t know how this was resolved.

 

[St. Paddy]

The block marker on the down at Drayton park is beyond the platform end signal.

I asked a trainer if the signal is red and a driver is operating in level 2 and has MA to that block marker, but for some reason stops beyond the red, is that a Spad ?. They said yes, even though the driver is not driving to the lights on sticks. I thought that odd.

(Assuming it is ECS so stopping for platform duties isn’t required. The train isn’t gapped as the rear shoes should be on the third rail still so no other operational incident has occurred)

Despite the block marker being beyond the signal (as it is at all NCL stations), you don’t get a movement authority beyond the signal at Drayton Park

 

[Belperpete]

Much of this discussion is fascinating. It might be worth remembering that all this will have been though through:

• During the pan European development of ERTMs (incorporating ETCS and GSM-R) Some twenty plus years ago. The U.K. was represented on the steering committees by what is now Network Rail and certainly Westinghouse (former colleagues) and possibly Alstom, others may confirm.

I doubt that Alstom were representing the UK back then, I suspect that it was Adtranz (as successors to GEC), or one of their precursors. I had some involvement through the aborted WCML ETCS project. I can remember that my Swedish colleagues were getting quite upset about how the French and Germans were trying to "corrupt" the ETCS concept to try and align it with their existing systems, and were desperately looking for allies to thwart them.

The UK railway was in a very different place back then. Railtrack was very hands off as far as any development work were concerned. Their attitude seemed to be that if we tell you what we want, then that will limit your thinking. If we don't tell you what we want then we will likely get something better and cheaper! But if we don't like what you have come up with, then you will change it for free! Heads I win, tails you lose. It led to some absolutely farcical situations in meetings.

Whereas Railtrack were very hands off, HMRI by comparison were very involved. They were reluctant to tell us what to do, but were at least very up front in telling us what they would not approve. As I posted previously, they were very concerned about drivers receiving conflicting information from cab and lineside, which was leading us down the path of providing an ETCS aspect on conventional signals. Drivers passing red signals at speed was a no-no, as was extinguishing the conventional signals (as an extinguished signal means stop).

Of course, neither Railtrack nor HMRI are involved now.

 

[choochoochoo]

Despite the block marker being beyond the signal (as it is at all NCL stations), you don’t get a movement authority beyond the signal at Drayton Park

Isn’t your movement authority up to the next block marker (not the signal). I’m pretty sure the distance to target isn’t 0 at the signal.

 

[JN114]

Isn’t your movement authority up to the next block marker (not the signal). I’m pretty sure the distance to target isn’t 0 at the signal.

No, movement authority will be to the red signal.

I don’t believe it is acceptable (in UK practice at least) to give an MA conflicting with a colour light signal displaying a red aspect; and the interlocking should be enforcing that.

 

[St. Paddy]

Isn’t your movement authority up to the next block marker (not the signal). I’m pretty sure the distance to target isn’t 0 at the signal.

Checked it today, it’s 10m of movement authority when stopped correctly at the signal which coincidentally is about 10m short of the signal