Railtrack operations director Chris Leah has written to contractors warning that it intends to tighten supervision of working practices.
The latest Railtrack group safety survey reports an 18% increase in accidents involving maintenance gangs on the same period in the past year.
Steve Huxley, director of rail maintenance for Balfour Beatty, which carries out a quarter of Railtrack's total maintenance programme, agreed that safety had to be improved.
Huxley confirmed that Balfour Beatty had received a letter about safety from Leah but said: "We have succeeded in reducing our accident rate in the last year and are working closely with Railtrack to achieve a zero accident rating."
Huxley said all Balfour Beatty operatives and subcontractors received daily risk assessment briefings on site as part of the company's campaign to improve safety.
The Railtrack survey says two construction operatives died last year and 58 operatives suffered severe injuries, an increase of 20 on 1997. The report also highlights a number of near misses involving workmen on the line and problems with the positioning of speed warnings.