The rail line between Brighton and Worthing is not expected to reopen until 6pm today after the Lancing crash.
The route has been shut since a Connex train smashed into a van on a level crossing in Old Salts Farm Road, Lancing, at 7pm on Wednesday.
The van driver and three passengers were taken to hospital with minor injuries. The driver was in a stable condition today.
A bus service is currently running between Shoreham and Worthing, with a rail shuttle from Shoreham to Brighton and from Bognor to Worthing.
Delays on the route today were similar to yesterday's, with an average journey time increase of 30 minutes.
The A259 and A27 were also busier than usual as rail-users took to their cars.
Wendy Toms, chair of the South East branch of the Rail Passengers' Committee, said the derailment had caused "horrendous problems" for people who normally use the line.
She said: "It is difficult to say whether the line could have been up and running quicker but it would be nice to think the crane could have got here sooner to put the carriage back on the rails."
Recovery workers moved in yesterday to remove the wreckage of the van and the damaged 180-tonne train, which was doing 50mph at the time of the crash.
A crane was brought in from Cardiff to perform the rescue - but at just 15mph it took hours to arrive.
The wreckage of the van was the first item to be removed at noon yesterday by a digging machine.
As it was lifted into the air it was hard to imagine how anyone could have survived the impact.
The front wheel unit of the train was ripped off in the impact and had to be replaced.
Andrew Munden, area production manager for Railtrack, said the service should be back to normal by 6pm today.
He said the plan was to re-rail the train and shunt it to Brighton with two locomotives, then replace the damaged track.
Inspector Mick Morriss of British Transport Police said: "We have still got quite a few inquires to conduct. It's going to be a joint investigation between ourselves and HM Railway Inspectorate.
"We have met with them and decided on a strategy to take this forward.
"I think we have got to look at what caused the accident and assure ourselves that whatever the reasons for it, the health and safety executive can come up with recommendations to prevent it happening again. There are a number of people to whom we do wish to speak."
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