JourneyCheck - thank you for the explanation.

[whole diary]

[grahame]

Quoting this as an example of a good description on JourneyCheck

Delays to services between Bristol Parkway and Cardiff Central

Due to a fault with the signalling system between Severn Tunnel Jn and Newport South Wales disruption is expected until 12:15 29/10.
Train services between Bristol Parkway and Cardiff Central may be delayed.
Customer Advice
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We are sorry for the delay to your journey.
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Some axle counters, part of the signalling system, have stopped working between Severn Tunnel Junction and Newport. Axle counters tell the signalling system if a section of track has a train on it. If an axle counter stops working, trains need to stop at the affected signal so that the Driver can speak to the Signaller to confirm if the track ahead is clear. Trains are able to run on other lines through the affected area, however trains have to run at a much reduced speed on these so some delays to services are expected.
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Network Rail have specialist staff on site who are investigating the problem.
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We will update this message with more information when we have it.

[Timmer]

There have been some improvements lately, particularly when a train is cancelled like giving the reader advice on an alternative service, though not always a good alternative.

[bobm]

TransWilts Community Rail has been working with GWR^▸ (Great Western Railway) (again) to encourage the running of alternative transport when there are cancellations AND to publicise them.    It does seem to bearing some fruit.

It has been less successful in getting the number of cancellations reduced.