A reader over at Muni Diaries sent in a few photos of the major track replacement project begun on Friday on the J-Church line at 18th and Church. The work ended around 4 a.m. this morning (hope everybody in the neighborhood got some good sleep last night!), and as Muni tells us, more pieces of the rail improvement project will continue on two as-yet-undetermined weekends at San Jose Ave and 30th Street.