What is the definition of 'fault'

[whole diary]

[PhilWakely]

18:18 Warminster to Cheltenham Spa due 20:50
18:18 Warminster to Cheltenham Spa due 20:50 will no longer call at Dilton Marsh and Avoncliff.
This is due to a fault on this train.
Last Updated:09/03/2018 14:58

I believe the service in question is a Turbo and the reason for not stopping is the absence of SDO^▸ (Selective Door Opening)?

In which case, since when has the absence of SDO been a 'fault'?

[grahame]

18:18 Warminster to Cheltenham Spa due 20:50
18:18 Warminster to Cheltenham Spa due 20:50 will no longer call at Dilton Marsh and Avoncliff.
This is due to a fault on this train.
Last Updated:09/03/2018 14:58

I believe the service in question is a Turbo and the reason for not stopping is the absence of SDO^▸ (Selective Door Opening)?

In which case, since when has the absence of SDO been a 'fault'?

That is my understanding of why that train's not calling too.

The term "fault" is applied quite widely - it basically covers things which render a train unable to (fully) be used to run a service it's booked for.   So lack of SDO is described as a fault, as is a train which can't do its full diagram because it would run out of fuel.   

Exceptions: if  train is stopped because it's run out of hour and needs a service, that may be described "more that trains requiring maintenance at the same time".

[SandTEngineer]

From OED^▸ (Oxford English Dictionary):

FAULT - A break or other defect in an electric circuit or piece of machinery