A days-long strike on the London Underground system took effect in earnest on Monday, upending millions of commuters’ journeys and threatening to disrupt life in the capital for most of the week, as workers protest over pay and conditions. Transport for London, the city’s transit authority, warned that “little or no service” was expected across the Underground network, known as the Tube, from Monday to Thursday after an initial, more limited walkout took place on Sunday. Up to five million passenger journeys are made each weekday on London’s Underground, which has 272 stations and 11 lines that crisscross the city and its surrounding suburbs. London’s buses were unusually crowded on Monday morning as commuters sought alternative routes to work. It was standing-room-only at about 9:30 a.m. on the 19, a double-decker bus, just a few stops after it began its rumble from residential communities in North London to more commercial districts in the city’s center, and there were long queues at many bus stations.
