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Re: NEWCASTLE ACCIDENT
In article <366EA2D9.E1C@acay.com.au>, Michael Van Baast <vanbaast@acay.com.au> writes...
>> The power was probably off within seconds of the accident. It wasn't
>>officially "isolated" until the earths were up.
>how do you effectively earth a train?,
Procedures will vary, they will be documented in the safety rules
of the relavant RR. Usually defined as to be executed by a trained
employee.
>weld thumping great big bits of copper between the body and the rail?
The ones typical in the US are roughly:
Using approved cables, connect between grounded metal
structure or rail and wheels or bodywork of vehicle.
Ground end to be connected first.
[prevents the ground being completd thru the groundor. If the
train is dead, it makes no differnce, if its 'live', then it
saves a life.]
Cables will have heavy spring jaws and/or screw type clamps,
and be of sufficient size to carry tripping current, forcing
a fault to open the breaker if necessary. Fitted to allow insulated
operation.
'grounding' is common in power industry, with standard practices,
Electric RRs are simply a special case. There are two issues requiring
grounding (more?):
The circuit might NOT be off, thru misoperation, or chance.
An off_but_ungrounded circuit can have lethal voltage &
current levels induced from live ones, especially with long
parallel runs (eg: RR OHLE).
thanks
dave pierson |the facts, as accurately as i can manage,
Compaq Computer Corporation |the opinions, my own.
334 South St |
Shrewsbury, Mass USA pierson@gone.enet.dec.com
"He has read everything, and, to his credit, written nothing." A J Raffles
"....the net of a million lies...." Vernor Vinge