There were no injuries in the train derailment

The group, based at Watton-at-Stone, Hertfordshire, said turnover had seen strong growth in the six months to 30 September.

Last year, the firm - which is at the centre of the Potters Bar rail crash inquiry - saw a 26% increase in turnover to �534.4m, with operating profits before goodwill rising by 20% to �29.1m.

The company was responsible for maintaining the section of track south of Potters Bar station, where seven people died when a train derailed on a set of points.

Investigations into the accident are continuing.

Coal train derailment

Jarvis has admitted it could be responsible for a derailment outside London's King's Cross station last month, after a damaged section being repaired by company contractors was not replaced.

Late last month the firm was also in court to answer a charge of breaching health and safety regulations relating to a coal train derailment near Rotherham in South Yorkshire.

The case was adjourned until 20 October.

On Wednesday, Jarvis said trading had been in line with expectations.

The group said the strong growth in turnover was principally due to its track work for Network Rail, particularly its �40m revenues from contracts on the West Coast Main Line modernisation scheme.

The turnover will also include a contribution from Jarvis' share of the turnover of the Tube Lines joint venture maintaining part of the London Underground, which it said continues to perform well.