Millions of U.K. commuters struggled to reach work Monday as staff on the London Underground subway system staged a 24-hour strike over station closures and job cuts.

Thousands of Tube workers walked out from 6 p.m. Sunday after their unions rejected last-minute proposals from management. Transport for London said services were “severely reduced” with 40 percent of stations closed, including the majority across central London.

“This Tube strike will cause misery to millions of Londoners,” London Mayor Sadiq Khan tweeted after the walkout began. The 150-year-old subway can carry 4.8 million passengers on peak days.

TFL said no trains were operating at all on the Victoria, Circle and Waterloo and City lines, and that while surface-rail services are unaffected there will be no subway connections at key terminals including Victoria, King’s Cross and Euston. Buses will be crowded and roads snarled, and those Tube trains that do run are likely to stop early on Monday evening, with the timetable not back to normal until Tuesday.

The Tube strike is the first of 2017 after walkouts last year over job cuts and ticket-office closures initiated by then Mayor Boris Johnson paralyzed London. The action coincides with planned strikes this week at the Southern rail franchise, which provides commuter services across most of southeast England.

More than 3,000 members of the Rail, Maritime and Transport union voted on the strike, with 85 percent backing action after 900 layoffs, according to a statement on the RMT’s website that cited a terror alert at North Greenwich last year and an incident at Canning Town when a passenger fell between a train and the platform as indicating how the measures have hurt safety.

RMT regional organizer for London John Leach said Monday in a BBC radio interview that the job cuts had left the Tube “falling apart at the seams” and had a “crushing” effect on staff.

Other striking workers are members of the Transport Salaried Staffs’ Association, where General Secretary Manuel Cortes said before the walkout that a TFL offer to increase staff was “a step in right direction” but lacked the required “urgency.”

London Underground Chief Operating Officer Steve Griffiths said the strike is “unnecessary” and that it had always intended to review staffing levels, with 200 extra staff to be recruited this year and possibly more. Customers are safe and fully supported, he said.