Engineers on Southern Rail are to stage a five day strike over claims of a "comprehensive breakdown" in industrial relations.
Members of the Rail, Maritime and Transport union will walk out from 5pm on July 12. They will also ban overtime over the weekend of July 10-12.
The move follows a 9-1 vote for strikes among union members at Southern, which operates commuter and other services between London and the Sussex coast.
The RMT said hundreds of engineers were involved in the dispute and warned that the strike will hit services.
Officials said under the 2013 pay settlement, a working group of union reps and managers was set up to find productivity measures that could cut the working week.
The union said the group could not find any way to bring in a 35-hour week with no extra cost to the company.
Productivity measures were subsequently brought in for engineers without leading to a reduction in the working week, said the RMT.
General Secretary Mick Cash said: "RMT will not stand by while agreed policies, procedures and agreements are unilaterally ripped up by Southern and promises on the reduction in the working week are kicked aside despite increases in productivity.
"As a result we declared a dispute and our engineering grades have now delivered a massive vote for industrial action and that programme of strikes and overtime bans will begin next week.
“In all of this, management have failed to show our members the respect they deserve as skilled and dedicated workers. We have made every effort to talk to the company about these issues, but have got nowhere. The only option we have is to use industrial action.
“Southern is a company intensively under the spotlight over its performance at the moment and RMT will not have our members left unrewarded as they hit work targets and then face a barrage of attacks on working conditions and procedures. RMT remains available for talks.”