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Post by Deleted on Nov 13, 2007 18:44:22 GMT
Evening all. Got to see a blueprint type layout of T5 today, and was told that LU services will be running into the sidings, from the westbound platform, and then back into the eastbound platform. Now surely it would be more faster and reliable to have drivers change ends in the platforms they terminate in, as all I see is a haven for point/signal failures that would screw up the service, when T5 is more busier?  Dave  |
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Post by Deleted on Nov 13, 2007 20:28:19 GMT
The crossover is west of the station so they have to use the sidings to change directions. Plus it keeps one platform for detraining and another for departing making it easiler for customers with baggage to wait for the train rather than hopping between platforms.
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Post by Deleted on Nov 13, 2007 21:43:43 GMT
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Post by Deleted on Nov 14, 2007 0:31:40 GMT
Exactly. Several threads in here have discussed the increase in capacity of T5 due to this design consideration - having a dedicated detrainment platform not only makes station duties easier, but also increases the number of trains that can be reversed at T5. Can you tell Ive been reading the above threads? ;D |
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Post by mrfs42 on Nov 14, 2007 0:41:51 GMT
Or that the varied extensions of the Picc in that area are shewing a lot of experimentation in terminal design? ;D ;D ;D If I was ever minded to write a textbook on such things I'd cite this end of the Picc [1]as the textbook example. No doubt stepkenk will be along in a bit with his words of wisdom and erudition. [1] HattonX westward. To qualify what I think - separate crossovers before the platform; scissors crossovers before the platform; scissors crossovers after the platform. All we need now to complete the set is a terminus with separate crossovers after the platform: T6 anyone?  <WTT geekery moment> I haven't finished looking at Wood Green reversers for Oracle because I got sidetracked with looking at the Picc WTTs and correlating them with the varied termini </WTT geekery moment> |
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Post by c5 on Nov 14, 2007 0:43:12 GMT
There should really be a crossover to the east of the station too. But this is a hell of a lot cheaper as it is!
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Post by Oracle on Nov 14, 2007 5:33:27 GMT
Of course at Hounlsow West you had an interesting three-platform arrangement, which was we now know the mirror image of the present-day Uxbridge. Without checking you had seperate crossovers, which Hatton X aped.
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Post by Deleted on Nov 14, 2007 9:19:30 GMT
Now surely it would be more faster and reliable to have drivers change ends in the platforms they terminate in, as all I see is a haven for point/signal failures that would screw up the service, when T5 is more busier? Faster - yes, but more reliable - no. Reversing trains beyond platforms is more reliable than reversing trains in platforms because a late running inbound train will not delay the next outbound train. It is the reversing method of choice on most modern metro systems. I would hazard a guess that this layout was designed for a few reasons - security, checking the train is empty of passengers and luggage, and improved passenger flow. Signal or points failures would cause similar capacity constraints with both types of termini, so that isn't an issue. Personally I think adding a facing crossover on approach to the terminus to allow late running trains to make up time would have been a good idea. However, this probably wouldn't have been cost effective, and would adversely affect the passenger flows in the station. LUL would have problems running high frequency services through this type of terminus due to their tipping out rules. However, as the Heathrow branch only runs approx 12tph, and T5 will only be getting half of that, then capacity is not an issue. |
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Post by tubeprune on Nov 14, 2007 10:46:37 GMT
The arrangement at T5 has the disadvantage that the reversing of trains restricts the headway unless you have an additional train to cover the time required to tip out (checking as well on LU) take the train into the siding, changing ends and bringing it back into the departure platform. As stephenk says, it shouldn't matter for T5 as the headway is long enough for the reversing move.
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<WTT geekery moment> I haven't finished looking at Wood Green reversers for Oracle because I got sidetracked with looking at the Picc WTTs and correlating them with the varied termini 
