(02-21) 19:09 PST CONCORD -- A BART train derailed Friday night near the Concord station, halting all traffic on the Pittsburg-Bay Point line and causing major systemwide delays. BART said the train derailed about 6:20 p.m. and was blocking tracks in both directions. No eastbound trains were moving beyond the Pleasant Hill station. The train was out of service, leaving the Concord station and heading to a nearby service yard when it derailed, BART said.