The 48 hour strike is the first of two being held in protest over plans to close ticket offices on the network and cut hundreds of jobs.
A second strike is due to take place from 9pm on Monday May 5th.
London Underground says mobile technology can allow staff to help customers without retaining ticket offices, thereby generating savings which can help keep fares down.
Managers insist some of the job cuts can be achieved by axing unfilled posts with others met through voluntary redundancy.
The RMT says the closures and job losses will lead to a worse service and warn some disabled passengers may be unable to get the help they need to complete their journey, claims disputed by LU.
On Monday talks at reconciliation service Acas broke up without the two sides reaching an agreement which would avoid strike action.
RMT Acting General Secretary Mick Cash said: “Despite the spin from LU nothing that they are proposing is about ‘modernisation’.
“The current plans, closing every ticket office and axing nearly a thousand safety-critical jobs, is solely about massive austerity cuts driven centrally by David Cameron and his Government and implemented by Mayor Boris Johnson.”
Labour and Green Party London Assembly Members have previously called for a public consultation on the closures, a proposal Mr Cash said the union agreed with.
Conservative and Liberal Democrat AM have criticised tonight’s planned strike and warned it risks damaging the capital’s economy and inconveniencing Londoners.
Caroline Pidgeon AM, Liberal Democrat transport spokesperson, called the strike “totally unnecessary” and warned it would “have a devastating impact for London’s economy and create the greatest disruption for ordinary Londoners, such as teachers and nurses.”
Ms Pidgeon blamed the strike on “a dubious mix of poor leadership by London Underground management and a leadership battle within the RMT positioning for strike action.”
Although she backed plans to make greater use of technology and said “getting some staff out from quiet ticket offices makes sense,” she said it was “simply wrong to consider ending ticket offices at such busy stations as Waterloo and London Bridge.”
Conservative AM Richard Tracey accused union bosses of “blocking” progress and said the dispute proved he and colleagues were right to push for a ban on Tube strikes and the introduction of mandatory, binding arbitration.
TfL says the following services are expected to operate:
Bakerloo Line: Between Queen’s Park and Elephant and Castle
Central Line: Between Epping/Hainault and Leytonstone. Between West Ruislip and White City
District Line: Between Wimbledon and Barking. Between Ealing Broadway and Tower Hill
Hammersmith and City Line: Between Hammersmith and Aldgate
Jubilee Line: Between Wembley Park and Stratford
Metropolitan Line: Between Harrow-on-the-Hill and Aldgate
Northern Line: Across the whole line with a train around every five minutes via Bank and Charing Cross branches in both directions.
Passengers are being urged to plan alternative routes and to check before they travel at tfl.gov.uk and by following @TfLTravelAlerts, @TfLTrafficNews and @TfLBusAlerts on Twitter.
