general secretary Mick Cash said: "Our members have been left with no choice but to call a further four days of strike action on SWR.
The action affects senior conductors in the RMT
Union who work on the company's local routes.
We are calling for the RMT
to call off this unnecessary industrial action so that planned Acas talks can go ahead."
"I want to pay particular tribute to RMT
members on Northern and South Western Railway, who will be striking again this weekend and on New Year's Eve in a long-running battle to put public safety before private profit.
blamed Arriva Rail North for the breakdown in talks.
General Secretary Mick Cash said: "RMT
continues to make every effort to get serious and meaningful talks going with Northern but the company are not interested and would prefer to continue to bury their heads in the sand regardless of the impact on the travelling public.
Now the Liverpool City Region Combined Authority, Merseyrail and the RMT
union have agreed in principle that the new fleet of Merseyrail trains "will have a second member of staff on board the train".
According to the RMT
, around 500,000 people use the Piccadilly Line daily.
"The company met with RMT
on Friday 8 June and further requests were tabled, but the union pressed for strike action.
members have shown extraordinary resilience and determination in the fight for rail safety and we thank the public for their continuing support and understanding."
"We are still prepared to offer unprecedented guarantees of jobs and pay reviews until the end of our franchise in 2025, with the Government guaranteeing jobs beyond that if RMT
ends strike action.
Andy Heath, Merseyrail managing director, said: "Yet again the RMT
has announced a further strike, remaining entrenched in a position to oppose any form of change with no desire to meet and reach an agreement.