Greater Anglia conductors will stop working overtime and rest days for four weeks.
The industrial action will run from October 10 to November 6.
It follows two days of strikes earlier this month by the RMT union over plans to allow drivers to operate train doors.
Greater Anglia says it will continue to run a full service.
Richard Dean, Greater Anglia's Train Service Delivery Director said: "During both days of RMT strike action we ran a good service for our customers. Our stand-in conductors safely operated more than 500 services each day.
"If the RMT ban on overtime and working rest days goes ahead, we will continue to run a full service.
"We value our conductors. We are guaranteeing all of their jobs right through to the end of our franchise in October 2025. In fact, we will also be recruiting more conductors.
"We're keen to talk to the RMT to try and agree a way forward."