A Waterloo Problem

[MaxB]

BARROW ON LINE MADE THE ROOF LIVE

"The metal roof at Waterloo, London, became 'live' yesterday after a porter's barrow caught by a train was dragged to a metal bridge where it short-circuited the electric rail and conducted the current to the roof. The current had to be switched off while linesmen cleared the track. No one was injured but electric trains were delayed for forty-five minutes."

Daily Mirror Jan 1st 1947

Discuss!

 

[Nym]

Trains ran on new years day???

 

[Darandio]

Trains ran on new years day???

Article is dated 1st Jan but references yesterday.

 

[Busaholic]

Trains ran on new years day???

Well, yes they did, it being a normal working day, but the article actually referred to New Year's Eve

 

[MaxB]

Yes it was presumably the previous day but in any case, New Years Day only became an English BH around 1980. Up till then it was nothing special. I was actually more curious about the electrical connection.

 

[edwin_m]

Would be interesting to know how long it was "live" for. These days you'd expect the breakers to cut out in the event of any hard short to an earthed object. However historically the protection was less comprehensive and it was more likely a short would persist until someone noticed and got the power shut off manually.

However, if the "short" has significant resistance then on the 750V system the fault current may not be enough to be detected as such, and this can result in a fire in the area of the short. But then the resistance from the roof to the earth should be a lot less than from the live rail through the short to the roof, so on the principle of the potential divider the roof should still be nowhere near the potential of the live rail.