The accident happened in September last year when the Balfour Beatty rail maintenance company was rectifying track that had become waterlogged through drainage problems.

A 21-wagon freight train was partly derailed and eight wagons hit a bridge, showering bricks onto a road at Rivenhall in Essex.

The case at Chelmsford Magistrates Court has been brought by the Health and Safety Executive.

The company is accused of having failed to maintain a safe method of repairing the track and of failing to ensure that rail passengers were not exposed to the risk of injury.

If convicted, Balfour Beatty could be fined up to £2,000 by the magistrates, but the bench also has the right to send the case to the Crown Court which has much heavier sentencing powers.