Tugger the SLUGger!SLUG Mailing List Archives

RE: [SLUG] OT NT on train timetable screens vs indicator boards


From: Stuart Cooper [mailto:stucoope@xxxxxxxxx]
>
>This one needs a video camera but I find it very interesting.
>
>Several times when I have been waiting for a train the time 
>for the next
>train has jumped back and forth 1 minute about every 8-10 
>seconds or so.
>
>So it will say the next train will be in 6 minutes
>8 seconds later the next train will be in 7 minutes
>8 seconds later still the next train will be in 6 minutes
>8 seconds later still the next train will be in 7 minutes
>8 seconds later still the next train will be in 6 minutes
>...and so it goes on. It is quite entertaining to watch, 
>particularly if
>there are later trains on display, their time jumps backwards 
>and forwards
>accordingly as well.
>
>I like to imagine the behaviour of the train that I'm waiting 
>for in my mind-
>it travels towards me for 8 seconds, making the arrival time 6 
>minutes, but
>then it goes into reverse for 8 seconds, causing the time to 
>change from
>6 to 7, then it travels forwards again... there's enough 
>problems on the
>trains as it is without shcizophrenic drivers.
>
>I haven't seen a blue screen of death yet (although when you 
>just miss a train
>and look at the blue application screen and see that the next 
>one is not
>for 30 minutes that is a blue screen of severe annoyance) but 
>I have seen
>the Windows desktop with a debug window open and what look to be error
>messages in an application window, there's lots of :: in them 
>so it might be
>C++ although it might be Visual Basic for all I know about MS.

That's C++.  VB doesn't do error messages like that.

Seriously, I'm working for Qld Main Roads up here and we do the software
that shows the time busses are due to arrive on signs at bus stops (as well
as the traffic signal systems).  Fact is that it is very difficult to
predict when a bus is going to arrive based on where it is now because you
have no idea what it is going to encounter between now and the stop.  All we
can do is go on a historical log of what has happened in previous days and
if that fails, the schedule.

Changing every 8 seconds sounds a bit silly to me.  If it is only displaying
times accurate to a minute then the programmer was stupid to update it at
more than 60 second intervals.  Most people don't set their watches by
trains, nor complain if a train is 30 seconds early or late compared to when
the sign said '1 minute to go'.

John Wiltshire