Yesterday ASLEF announced its members were due to strike on Tuesday August 1, Wednesday August 2, and Friday August 4 in a dispute over pay.
Meanwhile the RMT union, which has been fighting Govia Thameslink Railway over the introduction of driver-only operation, has instructed its members not to book any shifts on the same three days it announced today (Friday July 14).
The union has raised concerns about the potential loss of a second safety critical member of staff on Southern trains.
Mick Cash, general secretary of the RMT, said: “Yet again today RMT is forced to send Southern Rail a clear message that we will not allow them to strip the railway of a safety critical second member of staff on these vital rail services.”
ASLEF’s previous walkouts in December and January led to the complete shutdown of the Southern rail network.
The union has already implemented a ban on overtime working as part of the dispute over driver-only operation, which involves drivers being responsible for opening and closing train doors.
As part of the changes, guards represented by the RMT have been transferred to the roles of on-board supervisors.
A spokesman for GTR said: “To call three days of strikes spread across a week is a deliberate move to cause maximum disruption for passengers.
“To do so in protest against an offer to increase pay by 24% is simply breathtaking. Commuters, the vast majority of whom are seeing pay rises many times less, will understandably be as shocked and frustrated as we are.
“We absolutely need to modernise in order to increase capacity on this, the most congested part of the UK’s network, where passenger numbers have doubled in places in as little as 12 years. That requires modernisation of infrastructure, trains and working practices. The trade unions must join us in that endeavour.”
Mick Whelan, general secretary of ASLEF, said: “Now is the time for Chris Grayling and the Department for Transport to step in and assist in finding a resolution to a problem they caused.”