LONDON A major rail union raised the prospect of more travel chaos in London when it said on Wednesday it would hold a strike ballot among train maintenance workers on the London Underground, just two days after a walkout caused havoc for commuters.
The RMT union said London Underground management had gone back on agreements over work rosters and had not consulted with the union over reduced staffing levels.
"RMT members and the union will not stand by while an intransigent management attempts to ride roughshod over Tube workers. That is why we are balloting our fleet staff members for industrial action," said Mick Cash, general secretary of the National Union of Rail, Maritime and Transport Workers (RMT).
A spokesperson for Transport for London (TfL), the body that operates London Underground said: "The RMT is balloting for unnecessary strike action, this time involving train maintenance staff, without seeking to resolve these issues with us."
A 24-hour tube strike that hit millions of Londoners on Monday was called over a separate dispute involving staffing levels at stations.
The latest threat comes as thousands of commuters in the south of England were being hit by another rail dispute, over the planned introduction of driver-only trains which would eliminate the need for a guard to operate doors.
Nearly all Southern Railway services were canceled on Wednesday with another strike by drivers of the ASLEF union due on Friday.
The RMT also said on Wednesday it had issued a Jan. 26 deadline for Arriva Rail North to provide assurances that it would keep guards on its trains in the north of England.
"We have advised the company that should we not receive these assurances ... then our two organizations will be in dispute," it said.
(Reporting by Ritvik Carvalho; editing by Stephen Addison)