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| OTW and Tokenless Block - Train Complete? 10/07/2014 at 14:41 #62627 | |
Stephen Fulcher
2029 posts 
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When these systems were first introduced, was there ever a requirement for a signalman to have positive confirmation that a train was complete before letting anything else onto the single line sections? Am I right in thinking that nowadays any continuously braked train is assumed to be complete unless there is positive evidence otherwise? Log in to reply |
| OTW and Tokenless Block - Train Complete? 10/07/2014 at 16:01 #62630 | |
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Aaron86
25 posts |
For experience here in southern Italy, if you have a very long freight train, if you loose only the last (or few lasts) wagons, it's possible that the drivers may not have a clear evidence about it, as the conduct is soo long that the depression in the back doesn't arrive to the top of the train. Only evidences they might have are compressors always going and a little more traction effort required.
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| OTW and Tokenless Block - Train Complete? 10/07/2014 at 16:25 #62632 | |
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kbarber
1712 posts |
Tokenless Block Regulatins in the 1972 block book refer to the train '...having arrived complete with tail lamp' so it would appear that positive confirmation was originally required. By OTW I imagine you mean the sort of system on the Barnstaple Branch? There's nothing relating to that in the '72 Block Regs, although there is a section for '...single lines by the Absolute Block System with Train Staff or Train Staff and Ticket Working', which I take to include the traditional 'One Engine in Fume' system that later became OTW. The Watford - St Albans branch is worked by a similar sort of OTW without train staff. It was worked under special instructions in the Sectional Appendix (at least as late as 1980) and, presumably, in Watford Junction SBSIs. There is no reference to the train having arrived complete except when the single line has been cleared after a failure, in which case '...the Guard must give an assurance to the signalman at Watford that the line is clear throughout'. If the signal controlling entry to the single line cannot be cleared it was required to be worked by Pilotman. Hope that helps. Log in to reply |
| OTW and Tokenless Block - Train Complete? 10/07/2014 at 16:32 #62634 | |
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Stephen Fulcher
2029 posts
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By OTW I meant the system at Topsham to Exmouth, or Penryn to Falmouth in reality. Barnstable is actually token worked with NSKT overseen by Crediton Panel. Log in to reply |
| OTW and Tokenless Block - Train Complete? 10/07/2014 at 17:59 #62635 | |
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JamesN
1578 posts
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Can't answer your question on how thing were - but I know that nowadays all trains are assumed to be continuously braked - indeed it was this assumption that allowed them to temporarily introduce OTW between TVSC and Slough Panel when flooding knocked out most the signals and track circuits between Maidenhead and Twyford earlier in the year.
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| OTW and Tokenless Block - Train Complete? 10/07/2014 at 18:29 #62636 | |
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Late Turn
696 posts |
The assumption that all trains (at least along the line in question) are continuously braked, and thus the risk of a divided rear portion being left unnoticed on the single line, was certainly key to the provision of Tokenless Block on a couple of sections at the eastern end of the Exeter - Salisbury line, as I understand it. I'm not sure whether any of the 'remote' OTW, without staff, sections have a requirement for traincrew to advise train complete, but I'm fairly certain that a similar assumption is made in at least some of those cases. Of course, when working through a failed track circuit, it's again assumed that the train has passed through complete - though at least with the mitigation of the following train running under caution. Not sure what the exact arrangements were between Maidenhead and Twyford, but it can't have been worked under OTW regs! Possibly some form of TCB reg 3.5 working? Log in to reply |
| OTW and Tokenless Block - Train Complete? 10/07/2014 at 18:52 #62638 | |
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Ron_J
329 posts |
" said:When these systems were first introduced, was there ever a requirement for a signalman to have positive confirmation that a train was complete before letting anything else onto the single line sections?In Scottish Region Tokenless Block (I can't speak for any other version) it is and always has been a requirement that a train must be seen to be complete with tail lamp, or an assurance obtained to that effect, before the block is cleared. " said: Am I right in thinking that nowadays any continuously braked train is assumed to be complete unless there is positive evidence otherwise?That assumption is incorrect in the case of sections worked under the Absolute Block regulations. Log in to reply |
| OTW and Tokenless Block - Train Complete? 10/07/2014 at 18:53 #62639 | |
headshot119
4869 posts |
" said:" said:Debatable, there are plenty of boxes which knock out on AB before seeing the tail lamp, albeit the section is continually track circuited, but what happens if you get a track clear when occupied?When these systems were first introduced, was there ever a requirement for a signalman to have positive confirmation that a train was complete before letting anything else onto the single line sections?In Scottish Region Tokenless Block (I can't speak for any other version) it is and always has been a requirement that a train must be seen to be complete with tail lamp, or an assurance obtained to that effect, before the block is cleared. "Passengers for New Lane, should be seated in the rear coach of the train " - Opinions are my own and not those of my employer Log in to reply |
| OTW and Tokenless Block - Train Complete? 10/07/2014 at 19:28 #62641 | |
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kbarber
1712 posts |
" said:" said:" said:Debatable, there are plenty of boxes which knock out on AB before seeing the tail lamp, albeit the section is continually track circuited,When these systems were first introduced, was there ever a requirement for a signalman to have positive confirmation that a train was complete before letting anything else onto the single line sections?In Scottish Region Tokenless Block (I can't speak for any other version) it is and always has been a requirement that a train must be seen to be complete with tail lamp, or an assurance obtained to that effect, before the block is cleared. Full track circuiting is considered equivalent to seeing a tail lamp - the signalman is able to satisfy themself that the train is complete. Where full track circuiting is provided from the box in rear authority to clear back will be given in the SBSIs; in my experience they also specified the track circuits that had to be clear after the passage of the train before TOS could be sent. In the two instances I worked there was also a requirement that if the train subsequently passed the box without a tail lamp, 'Obstruction Danger' was to be sent. " said: but what happens if you get a track clear when occupied? Do you mean a wrong-side failure? If so, it probably first needs to be said that there's quite a high likelihood of it being noticed and appropriate action being taken (with all the faffing that would follow in extremely short order). It's also pretty rare. But in the end, that is the sort of circumstance that can result in disaster and there may be nothing anyone can do once it happens (as at Clapham in 1988). Log in to reply |
| OTW and Tokenless Block - Train Complete? 10/07/2014 at 20:11 #62645 | |
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Ron_J
329 posts |
" said:Debatable, there are plenty of boxes which knock out on AB before seeing the tail lamp, albeit the section is continually track circuited, but what happens if you get a track clear when occupied?Authority may be given to clear back without seeing the tail lamp in the Signalbox Special Instructions for individual locations (based, no doubt, on a robust risk assessment under Network Rail Standard NR/L3/OCS/041/F2-03A) but the Rule Book as in force today (GE/RT8000 Module TS3 sections 3.2) is clear in the matter: " said: You must observe the train as it passes the signal box and make sure it has a tail lamp at the rear. Log in to reply |
| OTW and Tokenless Block - Train Complete? 10/07/2014 at 20:17 #62646 | |
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Danny252
1461 posts |
And I'm sure that any special instruction giving authority to clear back relying on TCs only will include instructions for trains that don't reliably operate track circuits, essentially requiring a positive confirmation that it's arrived complete and with tail lamp.
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