Over 40,000 railway workers, many across the south, are to be balloted for strike action.
If voted for, the RMT union has said it could be "potentially the biggest rail strike in modern history."
The votes comes as Network Rail intends to cut at least 2,500 safety critical maintenance jobs as part of a £2bn reduction in spending on the network.
The 15 companies include: Chiltern Railways, Cross Country Trains, Great Western Railway, South Eastern Railway, South Western Railway, Island Line and GTR (including Gatwick Express).
The government, which runs Network Rail says it is “overhauling the sector and moving it off taxpayer life support”.
Anthony Smith from Transport Focus talks about the impact on rail workers
They claim staff have been subject to pay freezes, threats to jobs and attacks on their terms and conditions.
The ballot opens today (Tuesday April 26) and closes May 24.
If members vote "yes" in the ballot, a national railway strike could begin as early as June this year.