The Transport and Salaried Staffs’ Association has been rallying staff on multiple networks for industrial action.
Workers from Avanti West Coast, CrossCountry, East Midlands and West Midlands trains could all go on strike if members vote in favour.
While strike action is not certain yet, if it goes ahead it could happen just before or during the Commonwealth Games this July.
The union has also served a notice to 6,000 Network Rail staff, giving them the chance to vote on a walk out in late July.
They will be able to vote from June 20 to July 11, and if successful will be able to strike from July 25 onwards.