Multiple train companies attempted to run their trains back in time last week, including a Thameslink train which took -55m (negative 55 minutes) from Gatwick Airport to the next station Three Bridges, departing 02:58 and arriving 02:03:
Or a South Western Railway train from Woking to Basingstoke taking -33m (negative 33 minutes), departing 02:49 and arriving 02:16 on the same day.
Or a rail replacement bus departing 02:31 at Eastleigh, arriving 02:03 at Totton.
I’m telling an April Fools’ Day joke, right? But the trains which ran back in time were not on today! They were on last Sunday, 27 March!
So what happened to the trains then? As obviously running back in time is impossible, they all suffered from an hour delay on that day (courtesy to Realtime Trains).
The train departed Gatwick Airport at 02:58 was actually scheduled at 01:58, so the journey planner guessed the delay correctly when departing, but failed to apply the same delay when arriving Three Bridges with actual arrival 03:03.
While the train departed Woking at 02:49 were similarly scheduled at 01:49 in the internal system as well, and suffered from 57 minutes of delay upon its final destination.
That’s because train companies tried to schedule trains to run at a non-existent local time! The United Kingdom has inherited the old-fashioned and annoying practice of changing its time zone twice per year which causes extra traffic accidents, switching from UTC to UTC+1 at 01:00 the last Sunday of March, causing the local time to skip from 01:00 to 02:00, and UTC+1 back to UTC at 01:00 the last Sunday of October, causing the local time to roll back from 02:00 to 01:00. Because railway scheduling is done on local time, and the local time 01:58 didn’t exist on that day, computer systems which tried to process that time would instead treat the time as 02:58 local time resulting in trains running back in time which is physically impossible. And on the ground, because the local time 01:58 didn’t physically exist as well so trains couldn’t physically depart on time and had to suffer a “delay”.
This really showed that these train companies are incompetent that they couldn’t even produce a schedule which can be run in reality, as such impossible schedules can easily be checked by running a program on the timetable.