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| Maltby/Worksop SGL Working 12/04/2011 at 18:00 #2819 | |
Quizman
276 posts |
6F03 is approaching Worksop but Worksop has not yet given OOS back to Maltby however Worksop was still able to obtain Line Clear from Maltby for 4D15. Is that allowed/supposed to happen? Would have thought that Maltby could not give line clear until he was sure 6F03 had cleared section.
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| Maltby/Worksop SGL Working 12/04/2011 at 18:00 #15041 | |
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Quizman
276 posts |
6F03 is approaching Worksop but Worksop has not yet given OOS back to Maltby however Worksop was still able to obtain Line Clear from Maltby for 4D15. Is that allowed/supposed to happen? Would have thought that Maltby could not give line clear until he was sure 6F03 had cleared section.
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| Maltby/Worksop SGL Working 12/04/2011 at 19:34 #15044 | |
jc92
3685 posts 
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the first train has cleared the tokenless block section (the shaded track) and so the line can be considered clear for the instruments you can get a line clear because the single line is clear. the first train is protected by the track circuits so its still not possible to send the second train into section "We don't stop camborne wednesdays" Log in to reply |
| Maltby/Worksop SGL Working 12/04/2011 at 20:41 #15045 | |
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Late Turn
699 posts |
Hmmm, I'd disagree I think. I can't think of anything in reality that'd be worked as implemented here, but Tokenless Block's not very much different (but the block instruments work differently, with 'offer' and 'train arrived' buttons, and an acceptance switch, if I remember correctly). I wouldn't have thought it'd be possible to actually 'accept' anything in the opposite direction until the 'train arrived' button had been operated for the first (equivalent to clearing back and restoring to 'normal', I suppose), for the simple reason that the train isn't proved complete until the tail lamp has been observed.
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| Maltby/Worksop SGL Working 12/04/2011 at 21:32 #15046 | |
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jc92
3685 posts
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this simply works as AB and aslong as the single line TC is clear the sims logic says maltby can accept a train. i never said it was like that in reality. as of course TB is alot different
"We don't stop camborne wednesdays" Log in to reply |
| Maltby/Worksop SGL Working 13/04/2011 at 07:01 #15057 | |
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Late Turn
699 posts |
I'm sure I've come across a similar installation (effectively AB over a short section of single line) where the block instruments for each direction were interlinked, preventing one being pegged up to 'line clear' until the other direction was showing 'normal'. I'm not sure whether that's exactly correct, but it'd make sense to me for the reasons above - plus if one direction is placed to TOL to protect an obstruction, the last thing you want is to be able to give a 'line clear' the other way. Finally, there is no track circuit through the single line - so how do you know, other than the position of the block instrument, whether it's occupied? Tom Log in to reply |
| Maltby/Worksop SGL Working 13/04/2011 at 09:51 #15060 | |
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kbarber
1742 posts |
Late Turn said:I'm sure I've come across a similar installation (effectively AB over a short section of single line) where the block instruments for each direction were interlinked, preventing one being pegged up to 'line clear' until the other direction was showing 'normal'. I'm not sure whether that's exactly correct, but it'd make sense to me for the reasons above - plus if one direction is placed to TOL to protect an obstruction, the last thing you want is to be able to give a 'line clear' the other way. Finally, there is no track circuit through the single line - so how do you know, other than the position of the block instrument, whether it's occupied? IIRC this is implemented between Bewdley South & Bewdley North on the Back Road (Danny, can you confirm - it's a long time since I did a turn there and memory may be playing tricks). It was certainly implemented between Kensington North Main & Kensington South Main on the Down & Up Platform. In both cases, of course, it was a very short section and it was possible to see from either end whether it was clear or not; both are additionally track circuited throughout (although at Bewdley there are no TCs covering the south end pointwork). (At Kensington the section was also permissive block, just to add to the interest.) If such a precaution was considered warranted under those conditions I can't conceive it not being provided in a situation like Worksop - Maltby where, as Tom says, the blocks (and the TRB if the job's being done properly) are the only way of telling whether the single line is clear or occupied. Log in to reply |
| Maltby/Worksop SGL Working 13/04/2011 at 14:44 #15063 | |
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jc92
3685 posts
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and the axles counters  i thought the 3rd line at bewdley was directional block opped by direction levers? "We don't stop camborne wednesdays" Log in to reply |
| Maltby/Worksop SGL Working 13/04/2011 at 22:17 #15067 | |
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Danny252
1461 posts |
If I remember correctly, the Back Road is direction lever with block instruments - in that trains are signalled on the block instrument, but the direction lever supposedly allows it to be pegged up in only one direction at a time. I must admit I've never worked the Back Road though - only done a few lever pulls in North and a day of through trains at South - so it's more of an educated guess going on the equipment setup than an actual answer! From what I've read, the original SVR plan involved an ETT section between the two over the back road (possibly tokenless). That got put to one side at some point, though... As for the original topic, I can't think of any system where it's possible to accept over single line in one direction before out of section (or equivalent) is given. It pretty much goes against the entire concept of signalling over single line... Log in to reply |
| Maltby/Worksop SGL Working 14/04/2011 at 13:33 #15075 | |
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kbarber
1742 posts |
Danny252 said:If I remember correctly, the Back Road is direction lever with block instruments - in that trains are signalled on the block instrument, but the direction lever supposedly allows it to be pegged up in only one direction at a time. I must admit I've never worked the Back Road though - only done a few lever pulls in North and a day of through trains at South - so it's more of an educated guess going on the equipment setup than an actual answer! Indeed; as I recall, the regulations for the Back Road are (or were - they may have changed since I last did a turn, but I can't see why) ETT so far as they apply in the absence of a token. I really am dredging the depths of my grey cell now, but I have an idea Line Clear precedes reversing of the direction lever (or might even be independent of it - I think I recall using the direction lever at BS to enforce the "no shunting at both ends simultaneously" provision, on the basis that it would lock BN's calling on & shunt signals, when there was a set of coaches in the platform. On that occasion the block wasn't used at all (in fact it was correctly at TOL) and in fact I suspect the preceding movement may have been in the up direction the previous day, so the direction lever could be pulled regardless of the position of the block.) Or it might, of course, be that the direction lever is only locked by line clear in the opposite direction (or by reversing the direction lever at the opposite end). You may get the impression I liked working Bewdley... it's always fun when there's a box at both ends of a station where shunting & such take place 
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