Rail unions have called £160 million in cuts as part of a bailout of Transport for London (TfL) "troubling" - and hinted at strike action.
Labour Party London Mayor Sadiq Khan announced the £1.7 billion lifeline to cash-strapped TfL, agreed with the Conservative government on Saturday night, in a Sunday morning tweet.
"It is deeply troubling for TFL staff that this short term deal is loaded with strings that amount to at least £160 million of cuts with the very clear threat of worse to come," Cash said.
"RMT has said from the outset that TFL staff who have been there day in and day out at the sharp end keeping essential travel operating and London moving should not pay the price for this pandemic. We will fight any attempt to attack jobs, pensions, working conditions and safety."
Transport Salaried Staff Association (TSSA) General Secretary Manuel Cortes gave the news a cautious welcome, but warned the bailout would be scrutinised for its impact on his members' jobs.
Both unions organise workers on the London Underground and suburban National Rail networks which carry up to 7 million passengers a day.
But Downing Street pointed out that the Freedom Pass for over 65s is paid for by London's 33 borough councils, not TFL. Central government also pays for free travel for schoolchildren who live more than three miles from their school or who receive free school meals.
Council tax bills for Londoners will have to rise by £30 to £50 for a band D home from April next year to pay for the bail-out.
Conservative London Assembly member Susan Hall said Khan had jumped the gun over junior Minister for London Paul Scully with his announcement.
And Shaun Bailey, the Tory mayoral candidate in next year's election, blamed Khan's "mismanagement" of TfL for the service having to be bailed out for the second time this year - after a £1.6 billion cash injection in May.