Quote:
Originally Posted by richard thompson
If they hadn`t got a method of managing gaps in the live rail ( more than one pick up)trains wouldn`t be able to change direction at points.
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This actually raises a very important issue. As a rule of thumb most third rail EMUs have pick up shoe at 'each corner', ie one on each side of the leading bogie and final bogie (with various exceptions - particularly on newer stock).
There are of course thousands and thousands of gaps in the conductor rail, and these are mostly configured so as NOT to be exactly 4 cars apart. This is particularly important for the normal stopping places such as stations, but there are locations where stopping at a signal can cause the train to become 'gapped'.
Local instructions or Company Instructions to drivers advise of this. One such place is on the Metropolitan Spur in London. Drivers of (4 Car) trains which are stopped on a red signal in the Down direction at the bottom of the slope are advised
not to move off if it clears to only a single yellow. They should should only move if they receive two yellows or a green. This is because stopping at the next signal places them in the middle of Metropolitan jn which is full of gaps, and if they do become stuck they will block all trains out of Charing Cross !
Another issue raised earlier in this thread is third rail in sidings and depots. This is another place which is extremely gappy and when you motor through the points at a depot the Line Light clicks on and off all the time. It's extremely easy to gap in a depot, and is an unannounced cause of many cancelled peak trains !
The advice to a driver of a gapped train is to 'Gravitate'. Which is a posh way of saying release the brakes and hope to hell that there's enough of a gradient for the train to roll gently back onto the conductor. I can promise that If that does happen you feel like Christmas has come early.
Regards
FP