A number of train services have been cancelled or altered due to the heatwave which has hit the UK.
-> LNER managing director urging people not to travel from London as trains at standstill
London North Eastern Railway said five services have already been cancelled this morning, while the 09:30 Edinburgh to Kings Cross service has also been cancelled.
Customers due to travel on the 09:30 service are advised to travel on the 10:00 service.
Ticket acceptance is in place with Thameslink, Great Northern, and Southern services, via any reasonable route, Great Northern said.
First Class on all Great Northern and Thameslink services are declassified for the rest of the day, Great Northern Rail said.
Great Northern Rail said on their website: "We are advising customers to use alternative routes wherever possible.
"Your journey may involve more changes than usual, and journey times will be extended, with trains also being busier."
Yesterday's record temperatures caused major disruption to train services.
Great Northern also has a heavily reduced service this morning into the afternoon, particularly on routes to and from Peterborough.
This is due to displaced stock from yesterdays disruption meaning they are not in the correct place to form their service.
Great Northern Rail said on their website: "Major disruption, particularly towards the end of the day, can have an effect on the following days service.
"Depending on the nature of the incident, more trains than normal may be taken out of service to either ease congestion or for additional safety repairs.
"Trains may also have been placed in the wrong depots or sidings overnight, consequently being in the wrong location for the start of the morning service.
You may be entitled to compensation if you experience a delay in completing your journey today.
Keep your train ticket and make a note of your journey, as both will be required to support any claim.
To visit the compensation page on Great Northern, click here.
On July 25, the managing director of LNER urged people to stay in London and not attempt to travel as trains are at a standstill at Peterborough due to the hot weather.
The speed limit of the East Coast Main Line is 125mph in normal circumstances. but the extreme weather means it was reduced to 60mph at the southern end of the line.