The Warm Hardies’ “Fast and Heavy” is the best song about locomotives since Bob Dylan’s “It Takes a Lot to Laugh, It Takes a Train to Cry”; it is the best Death Cab song since “405”; it is a song that will fill your eyes right up as you reach to press play again and again. (It is not a Death Cab song. But it comes close enough.) The Warm Hardies are a Seattle girl-guy duo who sing with quiet, untrained passion, their harmonies brushing against each other like a cashmere cardigan against oxford cloth. “Fast and Heavy” is their first song; the band tells me a full-band version is on the way, which would be exciting if it wasn’t already completely perfect.