UK-Rail Strike
Union leaders Monday raised the prospect of Britain facing its first national rail strike since networks were privatised 14 years ago.
The Rail Maritime and Transport Union (RMT) announced it was balloting 17,000 workers for industrial action over pay and conditions.
Ballot papers will be sent to more than 12,000 infrastructure staff and 5,000 signal workers after they rejected an "unacceptable" from Network Rail, which is responsible for track maintenance.
The dispute follows months of talks aimed at achieving a single set of terms and conditions for maintenance staff, many of whom have transferred to Network Rail from private firms.
The result of both ballots will be known on May 22 with the prospect that strikes could start a week later, at a time of the beginning of the holiday season.
The last national strike in 1994 was over privatisation of the rail network into regional services, which caused intermittent disruptions lasting three months.
The new threat comes amid a series of industrial actions this year over pay disputes taken by public sector workers, including teachers, lecturers and civil servants.