Network Rail (NR), under-fire over level crossing safety, is to reduce the bonuses that can be earned by its top directors.

But under the proposed new bonus regime, NR's bosses could still get deferred annual bonuses totalling 20% of salary.

This means that if performance targets are met, NR chief executive Mark Carne who is on £675,000 a year, could get an annual bonus of up to £135,000.

To be voted on at NR's annual meeting in July the new bonus scheme ends the existing scheme. That saw top executives not only eligible for a performance-related annual bonus worth up to 60% of salary, but also a three-year rolling bonus worth up to 100% of salary.

In January this year, the subject of NR bonuses was raised in a Court of Appeal judgment which saw NR lose its appeal over a £150,000 fine after a 2010 level crossing incident at Beccles in Norfolk in which a 10-year-old boy suffered life-changing injuries.

In March this year, the House of Commons Transport Committee, in a report on level crossing safety which was highly critical of NR, said: "Given that Network Rail has recently been held responsible for the serious accident at Beccles we would be very concerned if its remuneration committee awarded bonuses to executive directors this year. "

In addition, NR may have felt that it was under more pressure over bonuses due to a change of accounting procedures which means the company's net debt of around £30bn, already guaranteed by the government, will be officially on the government's balance sheet from September this year — adding to the national debt.

The proposed new bonus structure, to cover the five-year period starting April 2014, covers not only Mr Carne, but also NR group finance director Patrick Butcher, network operations managing director Robin Gisby and route strategy director Paul Plummer. To get the new bonus, they will have to beat targets in areas such as safety, punctuality and passenger satisfaction