The KLW SE24B or KLW SE20B is a low-emissions diesel switcher locomotive built by Knoxville Locomotive Works (KLWX). It is powered by a single MTU Series 4000 12V R54 diesel engine which develops a total power output of 2,400 horsepower (1,790 kW). To date, one SE20B locomotive has been produced for KLWX, and it operates on the Gulf and Ohio Railways. Furthermore, at least 6 SE24B locomotives have also been produced, including for the San Joaquin Valley Railroad.