The RP-210 was a streamlined 1,000 hp (750 kW) locomotive built in 1956 by Baldwin-Lima-Hamilton, specifically to operate with the experimental, all-aluminum Train-X coaches that the Pullman-Standard Car Manufacturing Company built. The model represented Baldwin's attempted entry into the lightweight passenger locomotive market, but only three of the low-slung diesel-hydraulic units were produced. The first was built for the New York Central Railroad to power their Ohio Xplorer train between Cleveland, Columbus, and Cincinnati, and a pair was purchased by the New York, New Haven and Hartford Railroad to double-end their Dan'l Webster, running between New York City and Boston.