3 MTH powered units with a Tunnel Motor on point. The SD9 is a Rail King scale diesel. Most cars are MTH Premier Line with a few Atlas O, KLine and Lionel cars. Southern Pacific had to use older locomotives such as this SD9 and was running on hard times in the 80's and needed to merge with another railroad to stay competitive like other mergers of the day. It was common to see locomotives from the 50's & 60's running thru the early 90's. After the SP/Santa Fe merger failed, SP did not have a dancing partner until Rio Grande Industries purchased the SP. After the D&RGW/SP merger SP had cash flow, and the SP started to buy newer locomotives, such as EMD GP60's, SD70M's, GE Dash 8 and 9 series. Then UP bought Rio Grande/SP. This MTH lashup is running on the blue line. The smoke units are turned off.