First Great Western trains coming into London from Berkshire are again affected today, the the line has advised commuters not to travel unless it is absolutely necessary.
A spokesman for the line said that floodwater is likely to continue to affect trackside signalling and safety equipment 'for some time'.
"While Network Rail work to fix the problem we will only be able to run five trains an hour between Paddington and Reading in each direction. This is around a fifth of the services that would normally be scheduled.
"This will continue until Network Rail lets us know it is safe to run a full service again.
"We strongly advise customers not to travel unless it is absolutely necessary, and to consider alternative routes."
