Full train services are returning to the stretch of track where a crash killed seven people 10 days ago.
All the carriages came off the rails during the crash at Ufton Nervet
First Great Western said the line serving Reading, Newbury, Pewsey and Bedwyn would fully reopen on Tuesday following the crash near Ufton Nervet.
Police are still investigating why a car was on the Berkshire crossing when the train hit it on 6 November.
The funeral of one of the victims, Emily Webster, 14, was held in Okehampton, Devon, on Tuesday morning.
The other passengers who died were Anjanette Rossi, 38, her daughter Louella Main, nine, Barry Strevens, 55, and Leslie Matthews, 72.
The high-speed crash also killed the train driver Stanley Martin, 54, and the car's driver Brian Drysdale, 39.
First Great Western said train services between London Paddington and the west of England that had been diverted or replaced by other services were running again.
A spokesman thanked passengers for their understanding, adding: "Our thoughts are with the families, customers and staff who were involved in the accident at Ufton Nervet."
The crash was described as a "tragic accident" by the government after a report found no fault with rail equipment or staff.
Mr Martin had had only seconds to brake before his eight-carriage train ploughed into Mr Drysdale's car at 1812 GMT on 6 November and derailed, an interim Health and Safety Executive report found.
Police are still investigating the possibility that Mr Drysdale had wanted to commit suicide.