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| 2-1? 01/04/2010 at 10:05 #1034 | |
Jsun
212 posts |
I'm passingly familiar with absolute block working. However I have a problem at Dunblane, in order to send the 2-1 to the box in rear the train has to pass 400yrds beyond the home and observed to be complete. However the trains that terminate will never pass the box so it can't be observed as complete am I missing something, am I right in guessing there is a camera or a double mirror of somekind?
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| 2-1? 01/04/2010 at 10:05 #8040 | |
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Jsun
212 posts |
I'm passingly familiar with absolute block working. However I have a problem at Dunblane, in order to send the 2-1 to the box in rear the train has to pass 400yrds beyond the home and observed to be complete. However the trains that terminate will never pass the box so it can't be observed as complete am I missing something, am I right in guessing there is a camera or a double mirror of somekind?
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| 2-1? 01/04/2010 at 10:12 #8041 | |
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AndyG
1842 posts |
Dunblane?
I can only help one person a day. Today's not your day. Tomorrow doesn't look too good either. Log in to reply |
| 2-1? 01/04/2010 at 10:27 #8042 | |
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ralphjwchadkirk
275 posts |
I haven't read my AB regulations for a very long time now so I could be wrong, but all you would need to do is observe that the train is complete before sending train out of section. The line only needs to be clear to the clearing point when accepting a train.
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| 2-1? 01/04/2010 at 13:46 #8050 | |
postal
5265 posts |
If anyone wants to check rather than indulging in speculation, the current rule books are all on-line at http://www.rgsonline.co.uk/Rule_Book/Forms/Live_Documents.aspx?RootFolder=%2fRule_Book%2fRule%20Book%20Modules . The module for Absolute Block Working on Double Track Railway is at http://www.rgsonline.co.uk/Rule_Book/Rule%20Book%20Modules/TS%20-%20Train%20Signalling/GERT8000-TS3%20Iss%203.pdf . JG “In life, there is always someone out there, who won’t like you, for whatever reason, don’t let the insecurities in their lives affect yours.” – Rashida Rowe Log in to reply |
| 2-1? 01/04/2010 at 15:43 #8055 | |
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Late Turn
699 posts 
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If the tail lamp can't be directly observed - for whatever reason - the Signalman still has to be certain that the train has arrived complete before sending 2-1. There's various means of doing that: a tail-lamp camera, continuous track-circuiting through the section, a "Train Arrived Complete" plunger or most simply the Driver 'phoning in to advise that he's arrived complete. Local instructions might require the latter in any case, if the train's detained (in a station, for example, as at Rochdale) before passing the box, but after passing the clearing point. For what it's worth, our box at Loughborough (and Rothley on the down, in some circumstances) has this problem - the section from Quorn used to be track-circuited throughout (prior to closure), but now the Guard advises that his train is complete upon arrival. Tom Log in to reply |
| 2-1? 01/04/2010 at 16:13 #8057 | |
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Late Turn
699 posts
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Just as an afterthought, having looked at the sim now: to add to Ralph's post - anything stopped within the clearing point requires the block to be at TOL to the box in rear, so you wouldn't normally send TOOS until the train has passed beyond the clearing point. The exceptions that spring immediately to mind are where the route can be set for another line which is clear to the clearing point on that line, or where Reg 3.5 (warning acceptance) is authorised or to be used. Anything standing in the platform at Dunblane would have passed clear of the clearing point anyway - though you'd have to block back for a move back out towards the LOS. The section from Stirling North (presumably with an IB signal - and not TCB on the down) appears to be continuously track circuited in that direction anyway, which, if the special instructions allow, means that the Signalman won't need to look for the tail lamp (not sure if I read somewhere that Stirling North can switch out - which would be a complication there)
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| 2-1? 01/04/2010 at 21:27 #8087 | |
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bill_gensheet
1413 posts |
Yes, Stirling North is switched out on Sundays Bill Log in to reply |
| 2-1? 10/04/2010 at 08:07 #8343 | |
Peter Bennet
5402 posts |
I did try setting the ability to switch out boxes but it was not satisfactory as it involved forcing signals to green in circumstances where the SimSig IECC platform required them to be Red- so was abandoned. Peter I identify as half man half biscuit - crumbs! Log in to reply |
| 2-1? 10/04/2010 at 13:21 #8350 | |
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Zoe
252 posts |
Jsun said:I'm passingly familiar with absolute block working. However I have a problem at Dunblane, in order to send the 2-1 to the box in rear the train has to pass 400yrds beyond the home and observed to be complete. I hope this doesn't sound too pedantic but the clearing point distances are 440 yards when the distant is a semaphore and 200 yards when the distant is a colour light. Peter Bennet said: I did try setting the ability to switch out boxes but it was not satisfactory as it involved forcing signals to green in circumstances where the SimSig IECC platform required them to be Red- so was abandoned. While not ideal would it not have been possible to provide auto buttons on the appropriate signals that could only be used when a "block swtich" is activated? This way you could effectively send 7-5-5 to the boxes in both directions, operate the block switch and then clear your signals and set them to auto before leaving the box. As I say I know this is not ideal but would be better than nothing. Log in to reply |
| 2-1? 10/04/2010 at 13:36 #8351 | |
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Peter Bennet
5402 posts |
For the purposes of the Sim the clearing points have to be based on actual TC lengths as that's all I have to test against. The problem was not getting the thing to work as such it was forcing a permanent Green display. I guess I could have just coloured the signal Green while it was actually at Red with the interlocking preventing the inevitable 'train stopped at a G signal' query. Anyway it was an idea that came and went and I don't propose to revisit in the near future. Peter I identify as half man half biscuit - crumbs! Log in to reply |
| 2-1? 11/04/2010 at 12:46 #8383 | |
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Late Turn
699 posts
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Peter, Clearing points are often extended beyond the standard 200yds/440yds so as to match block joints between track circuits, so it's not an unreasonable 'simplification'. I did wonder whether simulating the switching out of boxes would be feasible - providing auto buttons alone wouldn't really do it, because that location would still be able to function as a block post. The conditions for the box in rear's section signal to be able to clear would have to change (requiring the line clear to the clearing point at the second box, rather than the next, now switched out, box), which should mean that nothing would ever be able to approach any signal at a switched-out box when the interlocking required that signal at Danger. Tom Log in to reply |
| 2-1? 03/08/2010 at 17:05 #10424 | |
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Neil_Scott
4 posts |
The Scottish Region Sectional Appendix requires all trains entering loops on lines not worked by the Track Circuit Block system to phone in to the controlling signalbox to confirm they are complete. That covers the working at Dunblane for Platform 3. For trains that terminate on Platform 2, there is also an instruction in the ScR SA that the driver must phone in to confirm he is complete. EDIT: I should add as well that the Down line has a track circuit clearing point for Platform 2, but not for Platform 3 where the SA regulation applies. Jsun said: I'm passingly familiar with absolute block working. However I have a problem at Dunblane, in order to send the 2-1 to the box in rear the train has to pass 400yrds beyond the home and observed to be complete. However the trains that terminate will never pass the box so it can't be observed as complete am I missing something, am I right in guessing there is a camera or a double mirror of somekind? Log in to reply |
| 2-1? 03/08/2010 at 17:37 #10427 | |
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Danny252
1461 posts |
To dredge up some old terminology, this would be a case where the guard would "give a 147" - (the old?) Rule 147 stating that if the train does not pass the signalbox, but 2-1 must be sent, the guard must inform the bobby the train is complete. Out of interest, with TCB on Network Rail, can the track circuit be used to give 2-1 with freight trains, or must it be observed complete? On the SVR, whilst Passenger Trains or Light Engines between Kidderminster and Bewdley South can be signalled as Out Of Section as soon as the track circuit shows they are past the CP, it cannot be used for Freight Trains due to the fair chance that wagons may have been sat in sidings for a long time, hence have rusty wheels and not operate TCs correctly. I always enjoy the TC demonstrator model in our signalling school, where the wagon used as part of the demo has gained rusty wheels itself, perfectly demonstrating this point! Log in to reply |
| 2-1? 03/08/2010 at 17:47 #10428 | |
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Zoe
252 posts |
Danny252 said:Out of interest, with TCB on Network Rail, can the track circuit be used to give 2-1 with freight trains, or must it be observed complete? Not TCB but on the up line between Truro and Par there are axle counters. Even though this is AB, when the signalman at Par sees 3 sections occupied and then cleared they can immediately clear back to Truro without having to observe a tail lamp. Log in to reply |
| 2-1? 03/08/2010 at 18:16 #10431 | |
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Late Turn
699 posts
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With double line TCB, there's no need to give 2-1 at all. Single line TCB is slightly different of course, but track circuits prove that the train has passed clear of the section; 2-1 is more to satisfy the method of working (obviously the SVR case is slightly different again owing to local circumstances). As Zoe says, track circuits are sometimes provided on AB lines to enable the Signalman to send 2-1 when he would otherwise be unable to confirm that the train had left the section complete; Halifax to Mill Lane (Bradford) is a good example - the latter box is remote from the end of the AB section by a number of miles.
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