Look both ways before crossing Delmar, everybody: the Loop trolley, which has a special talent for being extra expensive and extra behind schedule, is hitting the tracks for "System Integrated Testing" (SIT) starting today and lasting until mid-January. This process is meant to access the system as a whole, with "special attention paid to powered interface with platforms, signaled intersections, switch points and safety mechanisms," according to a press release from the Loop Trolley Company.…