Sheffield commuters heading to London this morning face delays after a train was cancelled because of a signalling problem.
The 06.49 London St Pancras International service was cancelled earlier this morning, leaving passengers having to plan alternative journeys.
Yesterday commuters faced disruption because of damage to overhead wires at Luton, National Rail said.
The damage has caused disruption on East Midlands trains between Corby, Nottingham, Sheffield and London St Pancras, while Thameslink services between Bedford, Luton and Three Bridges, Sutton, Sevenoaks and Gatwick Airport were also affected.
There could be some further delays today.