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| Re: TA is obsessed with CBTC, and ''New'' tech for no reason. (578960) | |||
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by trainsarefun on Sat Mar 1 16:17:51 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Stephen Bauman on Sat Mar 1 15:39:44 2008. It's the function of train supervision to insure that both leader and follower maintain the same speed profile and departing headway not the signal system.NYCT hasn't had much train supervision. Holding lights are not really up to the task. I've been running together the functional explanation for the signal system as has NYCT, in a way, I think. It seems that the shorter blocks on CBTC would be used to allow congested trains to move more closely behind each other, as in my example of the R, N, and W trains through 60th St Tunnel going into Lexington Av. (This functional explanation would also handle, if I'm not mistaken, thoughts about why short blocks were being used). In that way, perhaps NYCT will be using CBTC signals to squeeze more trains through non-terminal stations on the trunk line at irregular intervals, when trains bunch up? The train management side would be akin to preventing the drain from becoming overwhelmed in the first place, but on the CBTC signal side is it a better plunger, as it were, given that might be the use for trying to move more fluid down the drain, regardless of whether that fluid should have built up in the first place? Holding lights are not really up to the task. This is true. If applied at the right points, they can put an early train back on the timetable slot it's supposed to occupy, and it can hold two trains for a connection, but it's not likely to aid the train that's falling 30 seconds off pace, then 50 seconds, then 95, then 145, then.... Catch the delay when it's less than a a significant fraction of the frequency - and at 30 tph, that's 2 minutes - and maybe reducing dwell time at a few stations by 5 seconds at each can potentially get it back on track. It still won't work for catastrophic delays, but it's hard to find any good solution for those. E.g., on the Canarsie Line, a northbound train breaks down at Union Square - that's not pretty under any view of things; sure you can try to single-track around it, but at other than overnight frequencies of service, it wouldn't work out too well. But back to your point about train supervision, yes, it's used in other systems, it's used in video games (to good effect, don't laugh!), etc., so why not try something on the delay preventative side on NYCT? Yes, I'm agreed with that. |
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