Night Tube: RMT maintenance workers balloted on strike action
Maintenance workers belonging to the RMT union are voting on whether to strike over their Night Tube pay and conditions deal.
The dispute, affecting workers employed by Tube Lines, centres on pay and pension arrangements.
The RMT agreed a deal for its drivers two months ago, but said the one offered to Tube Lines staff was "inferior".
TfL said they would get the same 2% pay rise as LU staff.
The Night Tube was due to start in last September.
'Fair and sustainable'
Trains would run throughout Friday and Saturday nights on five Underground lines.
But Transport for London (TfL) struggled to secure a deal with the unions and the service is now expected to launch sometime later this year.
RMT general secretary Mick Cash said: "RMT members are furious at the cynical way that Tube Lines have attempted to tie in attacks on pensions with the offer on pay and night Tube, and our reps for this group of over 1,000 safety-critical staff have unanimously thrown the whole package out."
Steve Griffiths, chief operating officer London Underground, said: "We have made the same fair and sustainable four-year pay offer for Tube Lines maintenance staff as has been made for staff employed by London Underground.
"This will see an average 2% salary increase this year and inflation-protected rises in 2016 and 2017. Pension arrangements for Tube Lines maintenance staff have been the subject of separate ongoing discussions."