Simon Calder, a travel journalist, says the disruption at London Paddington train station could continue into the weekend.
A number of services, including trains to and from south Wales, were cancelled after signalling problems caused major disruption to a line.
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ITV Cymru Wales will publish the final poll of the Welsh Assembly Election 2016 campaign on Wednesday this week.
A mostly cloudy day with outbreaks of light rain and drizzle at times, mainly over the mountains where it could occasionally turn heavy.
The parents of a young boy from Anglesey say they're determined to find a missing dog that was bought to aid his recovery from surgery.