Deleted
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Post by Deleted on Nov 23, 2006 20:04:26 GMT
Which signal keeps falling over at Chalfont? Is it another one of those intermittent failures that make aetearlscourt's buddies scream and wail as they try to chase it down?
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Post by Harsig on Nov 23, 2006 20:29:33 GMT
Which signal keeps falling over at Chalfont? Is it another one of those intermittent failures that make aetearlscourt's buddies scream and wail as they try to chase it down? Most likely there is nothing wrong with the equipment. Chalfont always suffers multiple cases of signals remaining at Danger at this time of year due to the leaf fall. |
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Post by Deleted on Nov 23, 2006 20:34:33 GMT
Interesting. I thought Chiltern's Sandite workings combined with 6036 would help take care of that.
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Post by c5 on Nov 23, 2006 21:27:35 GMT
The soutbound inner home signal as failed a few times, then sometimes worked okay for following trains.
Chiltern Railways Sandite train is only permittede to lay on LU between Mantles Wood an Amersam. The water jetting train is allowed to spray anywere - if authorised by LU.
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Post by mandgc on Nov 24, 2006 0:28:24 GMT
Leaf Fall Signal Failures.
What causes the 'failure' ? Is it the wet leaves bridging the Block Joint and causing a short circuit ?
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Colin
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Post by Colin on Nov 24, 2006 0:52:06 GMT
I'm sure I'll be corrected if this is wrong:
The Met uses sequential signalling. In essence, as a train travels along the tracks, the track circuits 'drop' and 'pick up' - but if they don't do it in the correct order, the sequential signalling picks this up as an error and maintains the signals at danger (fail safe).
The leaves wouldn't create a short circuit across a block joint - you need metal for that, but they could theoretically insulate the train wheels from the rails preventing train detection and thus correct operation of the track circuits.
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Post by Deleted on Nov 24, 2006 16:13:34 GMT
The Met uses sequential signalling. In essence, as a train travels along the tracks, the track circuits 'drop' and 'pick up' - but if they don't do it in the correct order, the sequential signalling picks this up as an error and maintains the signals at danger (fail safe). Yes, however from what i heard it only applies to the track circuits before and after a signal where the Sequential signalling operates on. The signals that have been failing at Chalfont are JT77, JT5 & JT6 |
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Post by Deleted on Nov 24, 2006 20:05:18 GMT
on wednesday on the middles shift i had the good fortune to have jt6s throwing a wobbly due to the sequential, overnight i had an overrun of some works at jt imr and a treat was left after that: jt5s failing to clear and all s/b traffic being asked by me to trip past, i am happy to be at ricky tonight!
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