Great Western Coffee Shop

The train that checks lines for faults so that they can be fixed before there are problems that cause delays has ... itself ... been giving problems that have caused delays.

http://www.edinburghnews.scotsman.com/news/transport/fault-spotting-train-causes-23-rail-delays-in-3-years-1-3786977

Got me thinking ... of the 109 trains per week shown in the timetable to run all-stations services between Westbury and Swindon, how many
* are scheduled in the timetable when initially published
* don't get replaced by buses or different trains due to engineering
* never come under threat or significant doubt (strike action, potential engineering changes that don't happen)
* run as scheduled in that timetable or close enough to time to allow all connections to make

I have some statistics (and could get more) on immediate issues such as signalling and train failures, but a big part of the marketing comes down to people being able to plan well ahead and know it will run on the day - and that is a very different question to the stats that are put up at stations.