[LEAPSECS] No leapseconds on trains
igb at batten.eu.org
Sun Nov 20 06:01:52 EST 2011
On 18 Nov 2011, at 16:48, Clive D.W. Feather wrote:
> Paul J. Ste. Marie said:
>>> Hmm. In the UK the working timetable (not the public one) is written to a
>>> precision of half a minute.
>> This wasn't the timetable. Its main purpose, as I understood it, was to provide a record of where trains were, or where the dispatchers thought they were, in the event of an accident.
>> The logged locations weren't stops on the lines.
> Hmm, they may well be logging each track circuit transition
Track circuits? In manually-signalled USA?
Anyway, the average freight train in the USA is 6500 feet long (ie substantially over a mile) and travels at an average of around 20mph, or at most 30mph. So it takes around two minutes to pass a point. Timing that to a precision of a second seems a excessive. Each vehicle is of the order 20m long, so at those sorts of speed is going to take over a second to pass.
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