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Boom gates fail in Melbourne, limiting train services 27/08/2014 at 03:56 #64160 | |
maxand
1637 posts |
Quote:Malfunctioning boom gates have been swinging open as trains approach at level crossings on the Stony Point line south of Melbourne, forcing Metro to pull trains out of service and put passengers on buses to avoid the risk of a crash.Full article here. Anyone explain the connection between sand and faulty gates? Last edited: 27/08/2014 at 03:57 by maxand Log in to reply |
Boom gates fail in Melbourne, limiting train services 27/08/2014 at 05:10 #64161 | |
Hawk777
386 posts |
If I had to take a wild guess: the level crossing gates are controlled by track circuits rather than treadles, and sand is not electrically conductive resulting in failure to shunt the circuit? This would also explain why multi-car trains were not banned: much of the sand would likely have been brushed off the track by the time the later cars’ wheels arrived, letting them shunt the TCs effectively.
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Boom gates fail in Melbourne, limiting train services 27/08/2014 at 06:10 #64162 | |
kaiwhara
587 posts |
" said:If I had to take a wild guess: the level crossing gates are controlled by track circuits rather than treadles, and sand is not electrically conductive resulting in failure to shunt the circuit? This would also explain why multi-car trains were not banned: much of the sand would likely have been brushed off the track by the time the later cars’ wheels arrived, letting them shunt the TCs effectively.Correct. The Sprinter units over there are single car units, and some Stoney Point services are indeed operated by a single unit. Sanding is an issue if it is overused as it can cause a loss of electrical conductivity on a short train through the axle, therefore not causing the Track Circuit to appropriately drop in the presence of a Train. In New Zealand, the Standard Railcars which ran from the 30's to 70's were also well known for this. Sorry guys, I am in the business of making people wait! Log in to reply |
Boom gates fail in Melbourne, limiting train services 27/08/2014 at 07:20 #64163 | |
clive
2789 posts |
" said:If I had to take a wild guess: the level crossing gates are controlled by track circuits rather than treadles, and sand is not electrically conductive resulting in failure to shunt the circuit? This would also explain why multi-car trains were not banned: much of the sand would likely have been brushed off the track by the time the later cars’ wheels arrived, letting them shunt the TCs effectively.This is why automatic crossings in the UK always have two separate triggers, usually a track circuit and a treadle. If I recall correctly, the sample designs in the Green Book simply have the treadle short the track circuit. Log in to reply |
Boom gates fail in Melbourne, limiting train services 27/08/2014 at 08:35 #64165 | |
maxand
1637 posts |
Thanks guys for explaining this.
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