[LEAPSECS] No leapseconds on trains

[Ian Batten]

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.

> 

> Okay.

> 

>> 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.

ian