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| Re: SAS termini questions (126401) | |||
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Re: SAS termini questions |
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Posted by Rail Blue on Sat Aug 13 13:59:48 2005, in response to Re: SAS termini questions, posted by stephenk on Sat Aug 13 11:32:36 2005. I totally agree with you there. 35tph is an odd number. 34 or 36tph would be more sensible. As trains will be revesing in three platforms, then there will probably be uneven headways, as 33% movements conflict. Maybe this results in the 35tph?Which would suggest a real capacity of 462/3tph - which is itself a strange number. "Even if all platforms were used to reverse this 35tph, the most efficient way would still have all boarding on p4/5: 1) Train arrives on p1/2. 2) Train arrives on p3/4; train on p1/2 moves beyond station to relay on track 45. 3) Train on p3/4 departs; train on track 45 moves onto p5; train arrives on p1/2. 4) Train on p5 departs; train arrives on p3/4; train on p1/2 moves beyond station to relay on track 45. (repeat stages 3 and 4) " Some of the Paris metro termini with 3 tracks use a similar idea, with some trains relaying in sidings, and some trains reversing in a centre track in the station. It also helps with passenger flow as all passengers arrive on one island, and depart on the other. However, given LULs draconian tipping out rules, and the 4 minute driver end change rule, I think the above would get a bit too complicated to operate. Stepping back would probably sort it. Drivers of the middle track trains would need to step back two intervals. Drivers of the trains relaying beyond the station would have to drive the train forward onto track 45, then walk from the south end of p5 to the north end of p2 to board the rear of another train to drive it back north out of track 45 and up the line. This would probably mean stepping back three intervals. With the number of staff hanging around stations, tipping out shouldn't be a problem. Maybe one member of platform staff should be transferred to Morden from each of KXSP and Euston. Personally I think it would probably be easier to reverse trains in all three platforms, with drivers stepping back 3 trains (as will happen at Stratford on the Jubilee Line from next January). I suspect that LU will actually implement something like that. It's more their kind of way of doing things. If Bank vs Charing X trains ran in a 2:1 ratio (as they do in the off-peak at present), that would be even better for stepping back operations. I really don't see it working at Camden Town like that with 35tph. Within a day, trains would be backed up to Leicester Square. The scheme of operations I'd want to see would be: 17tph Morden - Bank - Golder's Green 12tph Morden - Bank - Finchley Central (or East Finchley if they can sort out the layout) 5tph Morden - Bank - Mill Hill East 17tph Kennington - Charing X - Edgware 17tph Kennington - Charing X - High Barnet |
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