Observing tail lamps

[edwin_m]

I've always understood that if a signaller working Absolute Block brings a train to a halt before its tail passes the box, they must observe the tail lamp or have confirmation from someone else that the train is complete before giving "out of section". However I've seen a suggestion on another forum that this wasn't necessary in the past for a "fully fitted" train, as the continuous brake was sufficient safeguard to confirm the train was complete. I've never heard of this practice - has anyone else?

 

[John Webb]

I've checked my copies of the Signalling General Instructions and Regulations from 1960, 78 and 2002 and can find no mention of such a provision. Could it have been a 'Special Instruction' issued only to specific boxes, perhaps?

 

[lineclear]

I've only known it authorised in the box instructions where the section is track circuited throughout.

(For anyone wondering why AB regulations would apply where the section is track circuited throughout, it's usually where there are points in the clearing point of the box in advance, so AB is needed for the safety of those points and trains routed through them.)

 

[edwin_m]

Slight correction. The situation relates to when a guard (in the back cab rather than in a brake van) reports a train complete with tail lamp to a signaller who can't actually see the lamp. The suggestion is that the guard can do this, and confirm to the signaller, without physically checking, on the basis that the train is fully fitted. But a signaller would have to see the lamp itself.

 

[ComUtoR]

Do/Have the rules ever specificed the method of confirmation ? Does it say the Signaller must visually check the lamps or is there just a requirement that they have to confirm the unit is complete ? Reading th eother thread regarding remote lamp checking I would say that a guard confirming the train is complete would meet the requirement of "confirmation" just not a personal check from the signaller.

 

[edwin_m]

I believe the signaller is able to rely on information from a guard, but the suggestion is that the guard can give this assurance without physically checking the tail lamp. This relates in particular to fully fitted freights in the era when they had a guard in the rear cab.

 

[lineclear]

If the last vehicle hasn't passed the box, but has passed the clearing point, and the signaller wants to 'knock out', the signaller can use another means to ensure the train is complete with tail lamp:

When it is necessary to send train out of section before the last vehicle of the train passes your signal box, you must make sure that the train has arrived, complete with tail lamp, before doing so.

 

[edwin_m]

If the last vehicle hasn't passed the box, but has passed the clearing point, and the signaller wants to 'knock out', the signaller can use another means to ensure the train is complete with tail lamp:

Absolutely. But is the existence of a continuous brake sufficient for the guard to give that assurance without actually checking?

 

[sw1ller]

Happens at Wrexham general P4 & P3. On arrival from Gwersillt, the guard calls the signaller to confirm the train’s complete with tail lamps. It’s completely out of sight for the signaller on P4. Probably on P3 too but I can’t quite visualise it. As for “fully fitted”, there’s possibly some confusion with the solid bar that ties an MU together, this extends the length of a train for certain rules but nothing to do with tail lamps.

 

[Tomnick]

I believe the signaller is able to rely on information from a guard, but the suggestion is that the guard can give this assurance without physically checking the tail lamp. This relates in particular to fully fitted freights in the era when they had a guard in the rear cab.

Although generally I don't think it'd be acceptable to rely on brake continuity alone (otherwise, why bother with checking the tail lamp at all on an AB line?), the now-replaced WR Tokenless Block signalling on the Salisbury - Exeter line relied on a similar assumption in places if I'm not mistaken, where trains left a section where a signalman wasn't present (e.g. Tisbury). It's referred to here: BR(WR) Tokenless Block (trainweb.org).

The BR(WR) system depended upon the use of special block instruments, track-circuits and treadles. Track-circuiting did not extend through the block section itself and only a treadle and two short track-circuits at the entrance to/exit from the block section were required for the operation of the basic system, although in practice the passing-loops tended to be fully track-circuited (and needed to be so at signal-boxes that could 'switch-out'). The avoidance of the need to track-circuit the entire block section reduced the installation costs, but it did mean (in principle) that a signalman had to be present at the exit from a section to check for a tail-lamp to ensure that the complete train has left the section. This was not considered to be a problem in the case of the Salisbury - Exeter line at the time of the original installation, but subsequent alterations resulted in a number of locations (both on that line and elsewhere) where a train could leave a single-line section remote from the controlling signal-box. In such cases reliance was placed upon the fact that all trains normally using the section were fully-fitted with continuous automatic brakes and therefore there was a low risk that a broken coupling would leave behind one or more vehicles obstructing the section un-noticed.

 

[lineclear]

Absolutely. But is the existence of a continuous brake sufficient for the guard to give that assurance without actually checking?

No. The train could still have become divided. It occasionally happens even with continuously braked stock.

 

[Gloster]

No. Brake continuity alone is not sufficient to allow a guard or other authorised person to give tail-light advice to the signalman. They don’t actually have to see the tail-light, although they should, but they must be certain that the last vehicle is still attached to the train. There might have been a few - a very few - locations where there was some variation to this in local instructions, possibly for local trip workings, but it would generally be avoided as it defeats the whole object of having a tail-light.

 

[alangla]

If the last vehicle hasn't passed the box, but has passed the clearing point, and the signaller wants to 'knock out', the signaller can use another means to ensure the train is complete with tail lamp:

Pretty sure there’s a few locations, in Scotland at least, that use CCTV to allow the signaller to observe the tail lamp passing the clearing point.

 

[Oxfordblues]

There are tail-lamp cameras at Abergavenny Up Goods Loop and Sutton Bridge Junction Up Goods Loop, for example.

I once observed a mixed freight arriving at Didcot TC from Eastleigh East Yard with an intermediate tail-lamp where the portions from Marchwood and Millbrook had been joined, a potentially serious safety issue.

 

[Blockman]

Although generally I don't think it'd be acceptable to rely on brake continuity alone (otherwise, why bother with checking the tail lamp at all on an AB line?), the now-replaced WR Tokenless Block signalling on the Salisbury - Exeter line relied on a similar assumption in places if I'm not mistaken, where trains left a section where a signalman wasn't present (e.g. Tisbury). It's referred to here: BR(WR) Tokenless Block (trainweb.org).

The latest version of the Kent Sussex Wessex Sectional Appendix shows that it is still Tokenless Block between Wilton South and Tisbury Loop, worked by Salisbury box. So the reliance on brake continuity in lieu of the signalman observing the tail lamp would still seem to apply in that section.

 

[edwin_m]

There are also "one train in section" sections, normally dead-end branches, where the returning train proves the section clear by sequential operation of two track circuits. These would also have to rely on continuous brakes to address train division risk.

More recently these would probably be done by axle counters, which do prove that the entire train has passed out of the section.

 

[Wilts Wanderer]

An example of where a signalling enhancement has changed the way the rule applies, might illustrate it better.

Prior to 2018 (I think it was) the Up line between Roskear LC SB (Camborne) and Truro SB was worked by absolute block without continuous track circuitry. Therefore the rule at Truro was that Train-Out-Of-Section (TOS) could not be given until the tail lamp was observed for an up train. As Truro box is located at the London end of the station and the section from Roskear was quite long - about 14 minutes for a stopping train - a CCTV camera was provided on Truro platform to enable observation to occur on arrival of an up train, rather than upon departure which would have added a further 2-3 minutes to the AB headway. However in 2018 (ish) intermediate block signals were installed in the Redruth area, which reduced the section length, and continuous track circuitry* was provided. This removed the need for the camera as TOS can now be given as soon as the overlap beyond the Up Home is cleared as an Up train approaches Truro station. The headway is now approx 7 minutes, reduced from 16-17 minutes previously, which makes a huge difference for timetabling. It’s worth noting that Absolute Block is still in place.

*Edit - it may have been axle counters, I’m not certain. It doesn’t make any difference.

There are tail-lamp cameras at Abergavenny Up Goods Loop and Sutton Bridge Junction Up Goods Loop, for example.

I once observed a mixed freight arriving at Didcot TC from Eastleigh East Yard with an intermediate tail-lamp where the portions from Marchwood and Millbrook had been joined, a potentially serious safety issue.

Is there possibly also a factor on the northern-end of the Marches Line that certain sections still retain their GWR-era track circuitry which has a lower safe detection reliability due to the early design? IIRC certain vehicles such as 2-axle examples (e.g. Pacers) and On Track Machines are not permitted to run under normal signalling regulations unless in multi-formation with a vehicle with more axles, as there is a greater risk of wrong-side loss of detection, particularly during leaf fall periods. I think this is why Pacers were never diagrammed north of Hereford, the one exception I’m aware of being an overnight 0030 Cardiff-Church Stretton which reversed in Shrewsbury station before returning ECS to Hereford. It was strengthened with a Pacer on busy nights (for example after match days in Cardiff) but the Pacer always had to be sandwiched by ‘better’ units.

 

[R JEB]

The Signal Box at Maidstone West is down from the station. Down trains {ie from Strood direction} terminating at Maidstone West do not pass the signal box and therefore there is a 'TAC' (train arrived complete) plunger at the up end of the down platform to be used after arrival. This also applied to trains continuing down beyond the station.

From my time as Guard at Gillingham, I used it many times. As an On Board Manager at Faversham, it is now the Driver's job, jovially referred to when crossing on the platform changing ends.

If it wasn't used, the signalman would not pull off for the up {towards Strood} journey or the down soon to be up journey {towards Paddock Wood}.

If the train was through to Paddock Wood or Tonbridge, once passing the centre of Maidstone West signal box, it would become an Up train.

 

[Llama]

Sometimes there are local instructions published in the sectional appendix for a driver to telephone the box and confirm that the train has arrived complete with tail lamp. This was the setup at Rochdale which allowed Rochdale East box to send TOS to Castleton East when that section was AB up until 2013.

 

[21C101]

It always surprises me a bit that the age old duty of a guard to observe signal aspects and apply the brake if the driver disregarded them was abolished.

 

[Wilts Wanderer]

It always surprises me a bit that the age old duty of a guard to observe signal aspects and apply the brake if the driver disregarded them was abolished.

The problem is that with colour lights, by the time a guard (assuming he’s actually in the rear cab / brake van) passes a signal it will have returned to danger, whereas often a mechanical stop signal would remain clear until well after the train had passed, giving him a chance to see it.

 

[edwin_m]

The problem is that with colour lights, by the time a guard (assuming he’s actually in the rear cab / brake van) passes a signal it will have returned to danger, whereas often a mechanical stop signal would remain clear until well after the train had passed, giving him a chance to see it.

The rule for a mechanical frame was and still is that the signal lever shouldn't be replaced until the train has passed over any points protected by the signal, otherwise the point lever would be free to be moved with the train passing over them.

It always surprises me a bit that the age old duty of a guard to observe signal aspects and apply the brake if the driver disregarded them was abolished.

In the days when that applied, there was no AWS let alone TPWS, many signals were badly positioned and lit and viewed past the long boiler of a steam locomotive, and pea souper fogs much more common. Even then the guard was only expected to observe signals when other duties allowed, and a surprising number of accident reports include statements such as the guard was filling in his journal, became aware they were going a bit fast and was just moving towards the brake handle when knocked over by the collision. So it was probably never that much of a protection and the risk is addressed these days by other means.

 

[LAX54]

The problem is that with colour lights, by the time a guard (assuming he’s actually in the rear cab / brake van) passes a signal it will have returned to danger, whereas often a mechanical stop signal would remain clear until well after the train had passed, giving him a chance to see it.

Some are last wheel replacement, some are first wheel replacement, we have trouble at Manningtree on the Down sometimes, to get a whole 12 car in, the front of the train passes the platform starter,some a simidgen further than others, this signal is 1st wheel, and drops back to red, the guard then refuses to give RA as the signal is red ! needs a few calls Driver / Guard / Signaller,

 

[MarkyT]

There are also "one train in section" sections, normally dead-end branches, where the returning train proves the section clear by sequential operation of two track circuits. These would also have to rely on continuous brakes to address train division risk.

These are technically very similar to one end of a tokenless block section in terms of the sequence of events required for block clearance. ISTR that in addition to the track circuits operated in correct sequence, both OT and TB also require a treadle operated and then normalised again as an extra safeguard.

Here's a simplified layout and circuit diagram for a tokenless block section from http://www.trainweb.org/railwest/gen/signal/tkblock.html

More recently these would probably be done by axle counters, which do prove that the entire train has passed out of the section.

An axle counter can have a single sensor solely at the entrance to a single track stub branch yet can provide full continuous train detection for any kind of train all the way to the buffer stops, even dealing safely with unfitted or partially fitted trains that could potentially split without both sections coming to a stand. Where an axle counter is provided on such a line, a big advantage of formally retaining the OT method of working, rather than converting to TCB, would be the avoidance of a platform starter signal for reversing at the terminus (and at any other routinely used intermediate reversing point en-route), which is a requirement for new installations under TCB regulations.

Another place where a tokenless block section routinely clears out automatically in both directions without tail-light observation is between Smallbrook Jn and the remote Sandown passing loop on the Isle of Wight. The section beyond Sandown to Shanklin is OT.

I remember being told by an 'old hand' in the WR Reading signalling drawing office that in the 1960s or 70s there was a serious proposal to formulate a new form of absolute block replacement to be known as 'Auto Block' that would have relied on similar principles to tokenless, and could have allowed remote automatic block sections on double track lines with neither remote tail light observation nor continuous track circuiting, with significant cost savings possible. Safety authorities of the time got cold feet I understand however and development was stopped, although TB (with automatic block clearance) was used for many years on the double track between Templecombe and Yeovil Junction. One of the lines was bidirectionally signalled with TB (sorry I forget which one!) although was normally only used in one direction, while the other unidirectional line used AB, which clearly needed manual block clearance with tail light observation.

 

[Gloster]

Templecombe-Yeovil Junction was AB when Templecombe was switched in (but see below), but at nights Templecombe and Gillingham were switched out and it was TB through from Wilton to Yeovil. The Up line was used in both directions between Templecombe and Yeovil. This allowed the Waterloo-Yeovil newspaper train to operate with minimal staffing. I think, but am not certain, that the Up and Down Reversible could be used in the Down direction under TB when Templecombe was switched in.

EDIT: It may have been that the Reversible could be used in the Down direction when Gillingham was switched in, but if Templecombe was in it had to be AB and right direction running between Templecombe and Yeovil. Gillingham is roughly half way between Wilton and Yeovil.

 

[MarkyT]

Templecombe-Yeovil Junction was AB when Templecombe was switched in (but see below), but at nights Templecombe and Gillingham were switched out and it was TB through from Wilton to Yeovil. The Up line was used in both directions between Templecombe and Yeovil. This allowed the Waterloo-Yeovil newspaper train to operate with minimal staffing. I think, but am not certain, that the Up and Down Reversible could be used in the Down direction under TB when Templecombe was switched in.

EDIT: It may have been that the Reversible could be used in the Down direction when Gillingham was switched in, but if Templecombe was in it had to be AB and right direction running between Templecombe and Yeovil. Gillingham is roughly half way between Wilton and Yeovil.

I'm pretty certain the bi-di TB line could theoretically be used in both directions at any time, whether Templecombe was switched in or out, but was rarely used in the 'wrong' direction routinely during the operating day because trains were nearly always timetabled to pass on that section around Sherborne. The whole weird setup was a legacy of the original singling project which went much too far and, in addition to other sections, took out the second track between Templecombe and Yeovil. Yeovil Junction signal box, although not demolished, had been stripped out, so had to be completely re-equipped inside with a new Western Region lever frame and electrical equipment when the second track (which luckily hadn't yet been removed) was reinstated a few years later!

 

[LowLevel]

The rule for a mechanical frame was and still is that the signal lever shouldn't be replaced until the train has passed over any points protected by the signal, otherwise the point lever would be free to be moved with the train passing over them.

In the days when that applied, there was no AWS let alone TPWS, many signals were badly positioned and lit and viewed past the long boiler of a steam locomotive, and pea souper fogs much more common. Even then the guard was only expected to observe signals when other duties allowed, and a surprising number of accident reports include statements such as the guard was filling in his journal, became aware they were going a bit fast and was just moving towards the brake handle when knocked over by the collision. So it was probably never that much of a protection and the risk is addressed these days by other means.

They are rare but first wheel replacement semaphores do exist - the motorised one protecting Broadfield Lane LC on the down at Boston puts itself back straight away and I'm sure there is another there that does as well but I can't remember which one.

 

[edwin_m]

They are rare but first wheel replacement semaphores do exist - the motorised one protecting Broadfield Lane LC on the down at Boston puts itself back straight away and I'm sure there is another there that does as well but I can't remember which one.

There is probably a track circuit starting just after the signal, primarily to work the crossing but it will also be brought into the signal controls. Normally a semaphore would be mechanically worked and therefore replaced manually. I think the signaller would be allowed if there were no points between it and the next stop signal, but they don't always know exactly when the train has passed the signal and may be occupied doing something else when it does.

 

[Gloster]

I'm pretty certain the bi-di TB line could theoretically be used in both directions at any time, whether Templecombe was switched in or out, but was rarely used in the 'wrong' direction routinely during the operating day because trains were nearly always timetabled to pass on that section around Sherborne. The whole weird setup was a legacy of the original singling project which went much too far and, in addition to other sections, took out the second track between Templecombe and Yeovil. Yeovil Junction signal box, although not demolished, had been stripped out, so had to be completely re-equipped inside with a new Western Region lever frame and electrical equipment when the second track (which luckily hadn't yet been removed) was reinstated a few years later!

I think that the original May 1967 singling left Templecombe-Sherborne as double, with Sherborne open as a box and Yeovil Junction reduced to a Ground Frame (for the Pen Mill connection). This only lasted a few months before the double line was extended to Yeovil, although I think that for a few years it ended just before the station. Down trains had to wait just outside the station if an Up was late.

 

[MarkyT]

I think that the original May 1967 singling left Templecombe-Sherborne as double, with Sherborne open as a box and Yeovil Junction reduced to a Ground Frame (for the Pen Mill connection). This only lasted a few months before the double line was extended to Yeovil, although I think that for a few years it ended just before the station. Down trains had to wait just outside the station if an Up was late.

Ah now that makes sense. For a few weeks in 1984 as a new trainee, I was attached to the S&T maintenance gang who looked after the old Southern route from Exeter to the (then) regional boundary at Sherborne. It surprised me the empty old box (a modern 60s design like some others on the route that had seen only a very few years service) still survived there. There was no equipment left, not even any legacy power or telecom cable terminations which still sometimes survive in abandoned installations and justify their retention, but the techs took me inside to have a look round the immaculate operating floor. They said it had been considered as a control point for the level crossing but that was located on the platform instead so the operator could also dispatch trains and sell tickets, although not any time close to departure clearly! I took no photos, unfortunately. The SB was demolished in 2011.