RAIL passengers face delays following signalling problems near Leamington.
Chiltern services between London and Birmingham have been reduced to one an hour, while speed restrictions around Leamington mean passengers face delays of up to half and hour.
Chiltern Railways tickets are being accepted on Virgin Trains West Coast, and London Midland services between Birmingham New Street and London Euston, and stations en route.
Tickets are also valid on First Great Western services into London via Oxford and Reading.
Chiltern services will be subject to short notice alterations, cancellations and delays.
Four London Midland trains which operate on the Snow Hill lines were stabled overnight at Leamington, and have been unable to move ready for early morning timetabled services.
Passengers travelling on London Midland services calling at stations between Leamington and Dorridge, in either direction, are affected.
A small number of services between Birmingham Snow Hill, Whitlocks End and Stratford have also cancelled as a result of the signalling failure.
Buses have been arranged from Leamington to Dorridge. At Dorridge passengers can join London Midland train services on the Snow Hill lines to Birmingham Snow Hill.