Union officials warned the strikes could cause rail passengers major disruption
Workers at three rail companies have voted in favour of industrial action over separate disputes, it has emerged.
The Rail Maritime and Transport Union said members at First Capital Connect and National Express East Anglia voted in favour of a strike over job cuts.
London Overground union members also backed strike action over an alleged breakdown in industrial relations.
The RMT warned of potentially "massive disruption". Firms said they were disappointed by the ballot results.
RMT bosses are now deciding their next move but co-ordinated strikes have not been ruled out.
Bob Crow, general secretary of the RMT, said its members had "struck a blow against selfish employers who are seeking to slash jobs solely to maintain profits and dividends".
"The scale of job cuts planned by operators across the railways threatens to undermine services, safety and the very fabric of an industry that is crucial to our economy and environment and it is vital they are stopped," he added.
Close to 800 union members at First Capital Connect supported industrial action by more than three to one.
Management is planning to cut 800 hours a week across 40 ticket offices, according to the RMT.
First Capital Connect expressed disappointment over ballot results and said a strike was "completely unwarranted".
A company spokesman said it was not planning any compulsory redundancies to the 14 roles affected, adding that talks with the unions would continue.
At National Express's East Anglia division, more than 300 jobs are under threat, said the RMT. Union members there backed action by two to one.
A company spokesman said there was disappointment a "minority" of RMT members had voted for possible strike action.
He said a business review had resulted in job cuts which had been met by managing vacancies and voluntary redundancies and carried out in consultation with union officials.
Meanwhile, the London Overground unions members voted 10 to one in favour of a strike.
London Overground Rail Operations Ltd (Lorol) said it was "astonished" by the RMT's claim of a breakdown in industrial relations.
A Lorol spokesman said: "All of the issues referred to [by the RMT] have been resolved, some, such as working conditions, as long ago as last year - to the full satisfaction of RMT representatives."
Liberal Democrat transport spokesman Norman Baker said: "I have great sympathy with anyone facing job cuts but 1970s-style strike action is not the way to pursue it.
"Going on strike will not get passenger support or prevent job losses," he added.
In another dispute, workers at South West Trains voted against a strike over job losses.