We have to laugh about this - it’s the perfect case of a single missing character screwing everything up.

On the evening of Wednesday 10th November, we had to restore schedule data to our database server after a problem importing it. These things happen from time to time, and there was due to be no issue. However, the process we carry out is to re-import the data on another server and then ship two SQL tables of data over to the database server. Here’s where the fun starts.

When exporting the data, we have to specify the names of the tables on the command line - ‘schedules’ and ‘schedule_locations’ in this case. However, we’d mis-typed them as ‘schedule’ and ‘schedule_locations’, meaning that only one of the tables was exported, not the second. We failed to spot the problem until after the data was restored, when that night’s timetable file was imported - creating a set of schedules for Thursday 11th November which were also wrong.

We ended up with a schedule database where all of the timing points of schedules were intact and grouped correctly, but the ‘header’ records were pointing at the wrong set of timing points. This is why you saw trains at stations destined for unfamiliar locations.

Once we’d identified the problem and were sure of the cause, we re-extracted and imported the correct set of schedule data, and baby-sat the site to validate everything was fine - which it is now.