Rail staff are to vote on industrial action after pension talks broke down between unions and Network Rail.
Unions are threatening the biggest rail strike in 80 years
Unions want employers to keep their pension schemes open to new staff, cap employee contributions and keep pension benefits at their current level.
However, Network Rail says the rail pension scheme is "sound and generous".
A strike, which could take place in mid-June, would be the first industry-wide railway stoppage since the General Strike of 1926.
Voting will start in a week, unions said, with staff including train drivers, engineers, ticket office staff and signallers expected to take part.
The Rail Maritime and Transport (RMT) union, Aslef, the Transport Salaried Staffs Association and the Confederation of Shipbuilding and Engineering unions have all called for rail pension schemes to remain open to all employees and worker contributions to be capped.
They want a deal agreed before what one union leader dubbed "unacceptably high" employee contributions come into effect in July.
But unions and management failed to reach agreement over the future of rail pensions.
"The employers have failed to give us the assurances we have been seeking to avert the pensions crisis facing us, so we have today given notice that we will be balloting our members across the industry for strike action." Bob Crow, general secretary of the RMT, said.
In response, Network Rail expressed its dismay at the strike ballot and suggested the unions were "unfairly using rail passengers and our employees as pawns in this political campaign."
"We are committed to the Railway Pension Scheme and seek constructive dialogue with the railway unions about how we manage the long term provision of pensions within Network Rail."
A Eurostar spokesman said the company was disappointed by the ballot.
"Eurostar offers a well-managed, responsible, equitable scheme and we not believe there are any grounds for a dispute."
Before rail privatisation, there was one salary scheme for British Rail workers.
Now there are more than 100 pension arrangements, involving at least 60 companies, including all the train operating companies and engineering firms which maintain the railways.
The unions have previously said there is a deficit of up to £600m among the pension schemes.
As a result, some workers could see their contributions double, unions have said.