[LEAPSECS] No leapseconds on trains
Clive D.W. Feather
clive at davros.org
Fri Nov 18 11:48:43 EST 2011
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 (I belive that
SSIs here do that). In which case a second is about the right granularity;
TRs normally have a delayed pick of a couple of seconds for safety reasons,
and the reporting time from trackside module to interlocking runs on a
basic cycle of several hundred milliseconds. So a 1 second error isn't
going to faze anyone.
--
Clive D.W. Feather | If you lie to the compiler,
Email: clive at davros.org | it will get its revenge.
Web: http://www.davros.org | - Henry Spencer
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