Bachmann HO Standard Line Alco S4 Diesel Locomotive, with Sound, Chesapeake & Ohio No. 5109
The Alco S4 switcher Chesapeake & Ohio No. 5109 includes Bachmann Sound Value SoundTraxx® diesel package with prototypical prime mover, 3 air horns, short horn, and bell - all in polyphonic 16-bit sound. Bachmann no. 63214.
The ALCO S4 were diesel/electric switchers manufactured by the American Locomotive Company (ALCO) and Montreal Locomotive Works (MLW). The S2 was similar to the S4 and differed only in trucks, with the S-2 using ALCO's own "Blunt" trucks, and the S-4 riding on standard AAR type A switcher trucks. Both were powered by ALCO 539 turbocharged, 6-cylinder diesels with 1000 horsepower. 1502 S-2s was built between August 1940 and June 1950 and 797 S-4s were constructed between June 1949 and August 1957 (MLW until 1957). Canadian production of the S-4 started more than a year before U S production of the S-4. ALCO did not start building the S-4 until August 1950.
A few S4s are still in service on shortline railroads around the US. Several are preserved in US and Canadian museums.