Further signalling problems caused delays to services between Havant in Hampshire and Chichester in West Sussex, between Shrewsbury and Wolverhampton and between Yeovil Junction and Salisbury in the West Country.
Another signalling problem, at Wandsworth Common in south-west London, led to delays to services through Balham station in south-east London, while illness to a passenger resulted in delays to services between Shenfield in Essex and London's Liverpool Street station.
No trains were able to run in and out of Moorgate station in London due to a lineside fire in north London. There were also delays in and out of another major London terminus - Waterloo - due to a signalling problem at Clapham Junction in south London.
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Wednesday morning's weather for the west of the region
Wednesday morning's weather for the east of the region
A new report into the ever- worsening traffic congestion in Oxfordshire has concluded that the county is in danger of coming to a halt.