Stencils on the Sill, Side Frame On full sill tank cars, the prefix and number of the tank car must be stenciled on the center sill. All tank cars for which the sill and tank were not built at the same time need to be stenciled with the prefix, number and built date. This stencil must be located on the sill at opposite corners of the tank car. This tank cardoes not require this stencil because the tank and sill were built at the same time. If a tank car has truck mounted brakes, the side frame must be stenciled with the date the air brakes were tested and/or repaired. The name of the company performing the test and the tank car identification number must also be stenciled on the side frame. The air brakes were tested by Comolli Rail Road Shop on 12-99. "TMBC 12-99 CRRS" indicates: TMBC indicates Truck Mounted Brake Cylinders. 12-99 is the test date. CRRS signifies that the Comolli Railroad Shop performed the test.