Twenty-one people were injured yesterday when a train struck a sewage tanker on a rail crossing.
Two people were in a critical condition and two more were seriously hurt in the crash shortly after 5.30pm at Little Cornard in Suffolk. Another 17 people were described as "walking wounded" .
Police arrested the driver of the sewage truck shortly after the collision between the vehicle and the National Express East Anglia rail service from Sudbury to Marks Tey, which was carrying about 20 passengers. Drivers wanting to use the crossing have to phone from the gate for permission to cross.
A spokesman for Network Rail said the signaller responsible for monitoring the crossing "did not receive a phone call from the user".
The train driver is thought to be one of the two casualties said to have suffered "life-threatening injuries".
Superintendent Phil Trendall, of British Transport Police, said the truck driver was arrested on suspicion of a number of railway safety offences. He added: "If the train had turned over the injuries could have been greater. We are just grateful the injuries were no greater in seriousness or in number."
Jack Barnett, who lives close to the crossing, said: "There was a very, very loud bang. I've never heard anything like it. I thought it was an aeroplane crash or a bomb going off. I came running out to see what had happened and we saw that the train had crashed. Two or three local lads had got down there sharpish and were helping people get off. The train was upright but the passengers had been knocked about."