LONDON (AP) — Tens of thousands of railway workers have walked off the job in Britain, bringing the train network to a crawl in the country’s biggest transit strike in three decades. Tuesday’s action could be a precursor to a summer of labor discontent. About 40,000 cleaners, signalers, maintenance workers and station staff are holding a 24-hour strike. Two more are planned for Thursday and Saturday. Major stations are largely deserted, with only about 20% of passenger trains scheduled to run. The dispute centers on pay, working conditions and job security as Britain’s railways struggle to adapt to travel and commuting habits changed by the coronavirus pandemic.