The RMT Union has called a five-day strike starting on Sunday 12 July.
Engineers employed by Southern are walking out in a dispute about changes intended to improve productivity.
The union said that members voted more than ten to one in favour of strike action, with concerns about the way the changes would affect safety.
Dozens are expected to take part in the walkout. If so, commuters from Brighton and Hove are likely to be affected by delays and cancelled services.
The RMT said that there had been a “comprehensive breakdown in industrial relations with the company”.
It held a ballot last month after Southern brought in new rotas without agreement. Engineers are also being given less time to carry out their work.
The RMT said: “Management’s approach to the implantation of the project is both intimidatory and aggressive.”
The union also wants the working week cut from 39 hours to 35 which it said had become the industry standard.
But, it said, Southern was not taking take the proposal for a shorter working week seriously.
RMT general secretary Mick Cash said: “Southern is a company intensively under the spotlight over its performance at the moment.
“RMT will not have our members scapegoated for failures at the top by outrageous and intimidatory demands to meet impossible work targets and through attacks on working conditions.
“The union is in no doubt that the pressure on these staff to deliver impossible targets compromises safety in what is clearly a safety-critical environment.”
