The RT-624 was an unpopular locomotive built by Baldwin. It was a dual-prime-mover engine for transfer service, back in the days when dedicated transfer engines were being built. Its general appearance - a massive 6-axle centercab - makes it impossible to confuse with anything other than a Baldwin DT-6-6-2000 or Lima T-2500 (see the threads on those models). http://www.rrpicturearchives.net/showPicture.aspx?id=183406 http://www.northeast.railfan.net/images/tr_prr8113.jpg PRR RT-624s. Note: No side sills. Step up in walkways. Alco-style trucks with the inboard axles closer, unlike most other 6-axle diesels. Headlight not at top of nose. Grilles at end of hood halfway up sides.