The Rail, Maritime and Transport (RMT) union has announced a batch of new strike dates in January across Northern, Merseyrail, Greater Anglia, South Western Railway, Southern and the Isle of Wight's Island Line.
The union has set a series of 24-hour walkouts in a bitter row over the role of the guard, and the extension of so-called driver only operation.
The issue has already caused significant disruption to passengers on Southern rail, with the row continuing for over a year, and while the train operator resolved its dispute with train drivers' union Aslef last month, it has not reached an agreement with the RMT.
|New strike dates|
|Members on Northern, Merseyrail, Greater Anglia, South Western Railways and Island Line have been instructed to walkout between 00.01 hours and 23.59 hours on the 8, 10 and 12 January 2018
Members on Southern have been instructed to strike between 00.01 hours and 23.59 hours on the 8 January 2018
The row has continued to spread to other train firms.
The RMT's general secretary Mick Cash said: "Every single effort that RMT has made to reach negotiated settlements in these separate disputes with the different train operating companies over safe operation and safe staffing has been kicked back in our faces and we are left with no option but to confirm a further phase of industrial action in the New Year.
"No one should be in any doubt, these disputes are about putting the safety of the travelling public before the profits of the private train companies."
The union said it remained ready for talks with the various train operators.
Andy Bindon, HR director at Southern parent firm Govia Thameslink Railway, said the RMT's decision was "even more regrettable as it comes on the same day that we had invited them to talks in the hope of reaching a resolution to their long-running dispute".
Richard Allan, Northern’s deputy managing director, said: "Northern is still prepared to guarantee jobs and pay for conductors for the rest of our franchise to 2025 if we can reach agreement on how our colleagues deliver better customer service using those fantastic new facilities. Additionally, last week the government wrote to RMT, guaranteeing employment for conductors beyond 2025 if RMT ends its dispute.
“RMT is striking yet again at Northern and at the same time on several other train operators. We will be working hard to keep customers on the move during these next RMT strike days.”
The strikes come on top of two one-day walkouts planned for Greater Anglia on the 27 December and South Western Railway on New Year's Eve.
SWR said it was "extremely disappointed" about further disruption to its passengers, at a time when many would be travelling to see family and friends, and said it had "repeatedly assured the RMT that we plan to keep guards on our trains".
It is already putting in place contingency plans for the 31 December strike, while Greater Anglia said it was disappointed to note the three extra strike days on top of the 27 December date, "as we have been holding constructive talks with union officials".
“We will be running our full Christmas service as planned if the RMT strike goes ahead next Wednesday, and intend to run a full service on January 8, 10 and 12," said Richard Dean, Greater Anglia Trains service delivery director.