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| Re: SAS termini questions (126275) | |||
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Re: SAS termini questions |
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Posted by stephenk on Sat Aug 13 04:35:46 2005, in response to Re: SAS termini questions, posted by Broadway Lion on Fri Aug 12 22:07:45 2005. Probly turn (Q) on one platform and (T) on the other.That probably wouldn't work, particularly at 28tph. After viewing the track maps, the 125th St terminus will actually have 3 tracks, 1 island platform, and 1 side platform, as opposed to the layout that I thought it had in previous posts (3 tracks, 2 islands) From observations in London at 3 track termini (with track layouts that allow for the least possible conflicts to departing trains - 33%), the sequence of operation for the highest capacity is:- (With track 1 being the inbound side, and track 3 being the outbound side) Track 1 - train arrives (can occur simultaneously with next movement) Track 2 - train departs Track 2 - train arrives (can occur simultaneously with next movement) Track 3 - train departs Track 3 - train arrives (conflicts with next departure) Track 1 - train departs and so on. Thus, if this sequence was used at 125th St, then the services would probably operate in the following order:- Q train - track 1 T train - track 2 Q train - track 3 T train - track 1 Q train - track 2 T train - track 3 and back to the start. Thus for any passengers wanting a specific train (Q or T), who have just missed a train on tracks 1 or 2, they will have to go back up the steps and across to the other platform. This is very likely to cause delays and/or injuries caused by people running for the trains and obstructing the doors, so as to avoid having to do a platform change. It also means that crews stepping back wil often have to transfer platforms too. This is probably not a problem under normal running conditions, but if trains start running out of sequence for whatever reason, then careful management of stepping back operations would have to be implemented to make sure the correct crew are on the correct platform! |
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