Rail unions face a series of challenges over the coming weeks after declaring disputes in key areas.
The RMT union has warned it plans to ballot 6,500 workers over industrial action unless an “acceptable” pay offer is tabled by London Underground (LU).
Union leaders said there was a “massive gulf” between workers and managers.
RMT union general secretary Bob Crow said, “From the start we have told LU that we would prefer a one-year deal.
“LU is insisting on a rigid four-year deal that our members told us they will not accept.”
In a separate dispute, 100 drivers on the Jubilee line will be balloted for strike action after one of their colleagues was sacked for passing a red light.
Driver Raj Nathvani has eight and a half years experience with no safety breaches, but was fired after he overran the danger signal.
The union also accused management of victimising Raj Nathvani’s RMT representative, Les Bruty, who faces disciplinary action and possible dismissal for a “minor incident” while driving an empty train.
And in a further dispute both Canary Wharf and Canada Water stations could shut if tube workers decide to strike over a “catalogue of harassment”.
Issues include a gay worker who claims to have been discriminated against and allegedly suffered homophobic remarks at the hands of bosses.