BART workers went on strike Friday morning, shutting the commuter rail line that carries 400 thousand riders a day. The strike came after contract negotiations broke down Thursday and the Federal mediator flew back to Washington DC. Union leaders say BART forced the strike by bringing up last-minute work rule changes, after agreements had been reached on the big economic issues like wages and pensions. The unions say they can have the trains running by 10 o-clock Friday night if management agrees to a plan that includes sending workplace rules to binding arbitration. Christopher Martinez reports.