Unions have threatened further industrial action for up to 7,000 signalling staff at Network Rail, after rejecting a two-year pay and conditions offer.
The Rail Maritime and Transport Union (RMT) has issued Network Rail with a seven-day ultimatum to improve its current offer, or face ballots for industrial action.
In co-ordinated referendums members of RMT and Transport Salaried Staffs Association (TSSA) voted heavily to reject an offer of 4.8% this year and the rate of inflation plus 0.5% in 2009.
Members of Unite have also been urged to reject the offer in a referendum yet to close.
The unions agreed to the offer for year one, however the second-year element would not protect members against the rising cost of living, they said.
RMT general secretary Bob Crow said: “By a margin of two to one, our members have voted decisively to reject an inadequate offer that would leave them less well off.
“Their verdict is quite clear and we have today told Network Rail that unless there is an acceptable offer on the table within seven days, we will put in place arrangements for a ballot for strike action.”
TSSA assistant general secretary Manuel Cortes said: “We are happy to accept 4.8% for this year but next year’s offer would mean a cut in our members’ living standards with soaring power bills and higher pension contributions.”