LONDON — Britain was crippled on Tuesday morning by its largest railway strike in three decades, halting trains across the country, throwing travel plans for tens of millions of Britons and visitors into chaos, and setting off what union leaders warned could be the beginning of a summer of labor unrest.
With last-ditch talks between the main union and the railway operator collapsing on Monday night, most trains ground to a halt for the first of three days of strikes. Most train service will…
