Piccadilly line Tube drivers to strike over 'bullying'
Piccadilly line Tube drivers have voted to strike after the RMT union accused London Underground managers of "bullying, harassment and intimidation".
The union says the "comprehensive breakdown in industrial relations" is related to problems with the "ageing" fleet of Piccadilly line trains.
Transport for London (TfL) urged the RMT not to "subject Londoners to another pointless strike".
No strike date has yet been announced.
The Piccadilly line, the fourth busiest on the Underground, has been the focus of a long-running industrial dispute over safety.
In January, a door opened on a moving train as it approached Heathrow, prompting an inspection of the whole fleet.
TfL said it was an "isolated incident", but the RMT denies this.
"There are major problems with the rolling stock that are not being addressed," a spokesman for the union told the BBC.
"Despite the fact that we've got members in the depot working to try to keep the fleet going, we've got problems with doors opening between stations, wheel flats [that affect braking] and signals being passed at danger."
RMT general secretary Mick Cash added: "Those issues have left drivers in a vulnerable position and have been used by management as a tool to harass and threaten members through misuse of the disciplinary procedure."
'Unnecessary strike action'
Pat Hansberry, Operations Director for London Underground, said: "It is disappointing that the RMT is once again threatening unnecessary strike action without seeking to resolve these local issues with us first.
"We urge the RMT to continue talks with us to resolve their issues rather than threatening to subject Londoners to another pointless strike."
Piccadilly line trains are known as "1973 stock", although they came into service later that decade.
They are now among the oldest trains on the London Underground.