Managers at railway stations in Birmingham are to be balloted for strikes in a row over pay and conditions.
Leaders of the Transport Salaried Staffs Association said if the 400 employees at 17 stations across the UK support industrial action it could cause "widespread disruption" during the summer holiday season.
The decision to hold a strike vote among the Network Rail staff followed the breakdown of talks over harmonising pay and conditions following a reorganisation of staff at all of Network Rail's stations.
Manuel Cortes, the union's assistant general secretary accused the company of refusing to guarantee that there will be no compulsory job losses during the reorganisation.
"We are acutely aware that the entire network could grind to a halt without our members overseeing safety and security for the travelling public at these key stations and we are anxious to avoid that situation if we possibly can.
"But Network Rail must sensibly address our concerns about a common set of pay and conditions for all our members. They must also lift the threat hanging over them of compulsory redundancies."
Staff at stations in Leeds, London and Manchester are also involved. Network Rail said it had contingency measures in place to keep the stations open in the event of a strike.
A spokesman said: "We are proposing a reorganisation of our stations to make them more efficient and more passenger focused. Contingency plans are already in place to ensure all duties at any of our stations can and will be covered."
The spokesman said there would be no impact on passengers or services if there is a strike because of the contingency plans in place.
