Some train services still disrupted by snow and ice
Rail journeys across Bedfordshire, Buckinghamshire and Hertfordshire continue to be affected by the cold weather on Friday.
First Capital Connect (FCC) said the Thameslink between Bedford and London would operate two trains an hour.
There would be an extra four journeys between St Albans to St Pancras at peak times, FCC said.
East Midlands Train is operating a reduced timetable, with an hourly service on the Corby route.
There will be three trains an hour on the London to Bedford line, with four extra services during rush hour, the train company said.
A statement on its website said all services were subject to delays and late alterations.
Forecasters have predicted a fine, dry day but still with low temperatures.
East Midlands Trains said passengers were advised to check for up-to-date travel information and leave extra time for their journeys.
Passengers taking connecting journeys across the three counties have been warned they face delays as a result of the problems.