The bridge from which a lorry fell in the Surrey train accident was assessed as safe in the nationwide checks made after the Selby rail disaster nearly 10 years ago.
The checks were ordered after a Land Rover came off the road and on to the East Coast Main Line in February 2001.
The vehicle was struck by an East Coast high-speed train which was diverted into the path of a freight train.
Ten people died in the tragedy and more than 80 were injured.
The Department for Transport and the Health and Safety Executive ordered checks of road bridges passing over rail lines.
A Network Rail (NR) spokesman said: “The Surrey bridge was assessed after the Selby crash and it was found to be well protected and not in need of any strengthening.”
Scores of other bridges were strengthened, with the checks mainly being carried out by local authorities with NR helping.
Train services will return to normal today along the track where the 26t cement mixer plunged from a bridge and on to a carriage, rail bosses said.
South West Trains said extensive repairs to the line had been completed, allowing the full re-opening of the commuter route.
It followed the removal on Saturday of wreckage from Friday’s accident, in which a handful of people were injured.
The incident happened when the lorry, travelling towards Leatherhead, Surrey, crashed into the wall of a bridge in Warren Lane, Oxshott, at about 3.30pm.
Part of the wall subsided, causing the lorry to plunge on to railway tracks below.
At the same moment, an eight-carriage train bound for London Waterloo was passing underneath.