Box Pulling. Returning from City Fiber Inc. in Vernon, California with a box car, UP 1373 (née-Southern Pacific 3198, EMD, GP40P-2, 11/1974) crosses East 23rd Street in Los Angeles, California on the return to J Yard with its signature “flatback” showing. This engine is one of 16 GP40 variants built by EMD for passenger service, its extended body capped with a flat back to accommodate a steam generator. Of the 16, this and sister unit 1375 are the only ones left with unusual feature. The others, Indiana Harbor Belt 4010 GP40P-2 and the 13 ex-Central Railroad of New Jersey units that now serve New Jersey Transit, have been rebuilt and have the more familiar angled cap.