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Post by Deleted on Oct 11, 2005 12:58:09 GMT
I was reading my copy of the Victoria Line history by Mike Horne and came across the diagram of the works at Finsbury Park (as reproduced by John Rowland at www.geocities.com/Athens/Acropolis/7069/ltfinpark.gif), and after looking at it there are some things about it which bug me. 1. Why does the diagram not show the step-plate cavern with the bricked-up portal north of the n/b Picc platform? Admittedly this part of the Piccadilly was the only part of the line whose track was not modified in this area, but I still curious as to whether or not it was put there when the Picc was extended or when the Victoria Line was built. 2. Are the original tunnels at the pair of step-plate junctions on the s/b Picc still visible, or have they been bricked up too like the remainder of the tunnels? 3. Did the station ever have lifts, and if so, are they blocked by any building works in the area or are they still clear? I've had the misfortune of using the station during busier periods and the traffic jam of people negotiating the small tube-size passenger tunnels and stairways is rather uncomfortable. Wikipedia and other places imply that the station never had lifts in the first place and that access has always been by staircase. 4. Why are the Piccadilly platforms humped like the GN&CR platforms?
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Post by Tomcakes on Oct 11, 2005 18:09:59 GMT
Picc platforms are humped as they were originally shorter and were extended AFAIK, cutting into the gradients either side.
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Post by piccadillypilot on Oct 11, 2005 19:07:20 GMT
Picc platforms are humped as they were originally shorter and were extended AFAIK, cutting into the gradients either side. That's the Central you're thinking of. The Picc platforms haven't been extended.
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Post by Tomcakes on Oct 11, 2005 19:18:02 GMT
Hmm... I think there's something in The Piccadilly Line by Capital Transport about FPK...
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Colin
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Post by Colin on Oct 11, 2005 23:31:34 GMT
4. Why are the Piccadilly platforms humped like the GN&CR platforms? Isn't that something to with going uphill on entry to platforms to assist slowing the train - then downhill on exit to assist acceleration ? BTW - when using the spell check facility, it suggests theonekea should be thinker. How appropriate !! ;D
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Post by q8 on Oct 12, 2005 4:04:22 GMT
Why are the Piccadilly platforms humped like the GN&CR platforms?
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I would suggest that as the Piccadilly was built after GN&CR it was just a matter of using the same profile.
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Post by Deleted on Oct 12, 2005 12:52:41 GMT
Isn't that something to with going uphill on entry to platforms to assist slowing the train - then downhill on exit to assist acceleration ? As i have found out in the past, the trouble is with Finsbury Park, it is more downhill than uphill!
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Post by Deleted on Dec 5, 2005 0:27:09 GMT
Isn't that something to with going uphill on entry to platforms to assist slowing the train - then downhill on exit to assist acceleration ? As i have found out in the past, the trouble is with Finsbury Park, it is more downhill than uphill!
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Post by Deleted on Dec 5, 2005 0:29:18 GMT
As i have found out in the past, the trouble is with Finsbury Park, it is more downhill than uphill!
there speaks a boy with experience ??
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Post by Deleted on Dec 5, 2005 17:54:46 GMT
It seems strange that the platforms are humped when the station used to be a terminus. Assisting acceleration into the end of the tunnel isn't a good idea!
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Post by Deleted on Dec 5, 2005 19:58:27 GMT
It seems strange that the platforms are humped when the station used to be a terminus. Assisting acceleration into the end of the tunnel isn't a good idea! IIRC, its on a RISING gradient into the station, both directions. When you leave, its on a DESCENDING gradient, therefore, you'll slow down on approach to the station, reducing brake wear, and, on departure, gain speed quicker... Beleive me, these tube builders knew what they were doing [after being shown how to do it...]
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Post by Deleted on Dec 5, 2005 20:38:14 GMT
It seems strange that the platforms are humped when the station used to be a terminus. Assisting acceleration into the end of the tunnel isn't a good idea! IIRC, its on a RISING gradient into the station, both directions. When you leave, its on a DESCENDING gradient, therefore, you'll slow down on approach to the station, reducing brake wear, and, on departure, gain speed quicker... Beleive me, these tube builders knew what they were doing [after being shown how to do it...] But if a train overran the stopping mark, the descending gradient would increase the length of the overrun. As I said is not a good thing at a terminus, which Finsbury Park was for many years. Unlike intermediate stations where a hump profile is preferred, an uphill slope towards the buffers would be more preferential at a terminus.
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Post by Deleted on Dec 5, 2005 20:50:48 GMT
[quote author=stephenk board=picc thread=1129035489 post=1133815094 But if a train overran the stopping mark, the descending gradient would increase the length of the overrun. As I said is not a good thing at a terminus, which Finsbury Park was for many years. Unlike intermediate stations where a hump profile is preferred, an uphill slope towards the buffers would be more preferential at a terminus. [/quote]
I guess that when Finny P was a terminus, there was sufficent length beyond the terminating platform to accomodate any 'risk' of a train overrunning the station. True yes, an uphill run into a dead end station would be ideal, this would have benefits other than reducing a risk of an over-run [platforms are closer to the surface, so less distance for the passengers to walk]
Downhill runs into stations can be problematic - especially in the open air, as you have to account for weather conditions, and the technical side of things; the trains might look the same, but these newfangled computer driven trains means that the Tractio and Braking capabilities can be set at different levels, this will affect performance and the T/Ops ability to control the train. I'm always making entries into my notebook if I sus a train is behaving oddly.
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Post by Deleted on Dec 5, 2005 21:34:26 GMT
I guess that when Finny P was a terminus, there was sufficent length beyond the terminating platform to accomodate any 'risk' of a train overrunning the station. True yes, an uphill run into a dead end station would be ideal, this would have benefits other than reducing a risk of an over-run [platforms are closer to the surface, so less distance for the passengers to walk] I would hope that given the hump profile at Finsbury Park, there was long overrun! Maybe it was designed to one day be a through station (which as we all know it was)? Downhill runs into stations also decrease the line capacity, as the signal overlaps are longer. Uphill runs into stations slightly increase line capacity with conventional signalling, but surprisingly slightly decrease line capacity with moving block signalling.
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