This isn't your high school chemistry lab. A RailWorks crew has just dramatically ignited a thermite weld as construction activities for Sound Transit's M Street to Lakewood Track and Signal Project draw to a close. This weld is joining a split-point derail panel to a length of 115LB rail on the Yelm Connection, which ties ST's mainline to the remaining Lakeview Sub trackage owned by BNSF (retained to serve McChord Air Force Base and Fort Lewis). Sounder commuter rail service to Lakewood won't begin until 2012, awaiting the long-delayed completion of the "missing mile" between D and M Streets in Tacoma. (Read more about thermite welding at Wikipedia.)