The RMT rail workers’ union is to ballot Network Rail workers denied bonus payments over the Grayrigg accident in Cumbria, and Scottish signallers docked a bonus for striking earlier this year.
The ballot of both groups will end on 25 June.
The RMT has warned that if these disputes are not settled a ballot of all Network Rail infrasructure and signalling staff will take place.
Some 119 Network Rail staff employed in the area that includes the site of the Grayrigg crash have been denied their £400 bonus.
Over 400 signallers and supervisors who took strike action over the company’s failure to honour an agreement have been docked £300.
The threat of strikes has shamed Network Rail bosses into suspending part of their own massive bonus payments.