The Federal Enterprises Thunderbolt 2000 was an early variant of Federal's popular Thunderbolt series, and was a gas-powered variant of the siren. Rather than using an electric motor, the siren's blower was powered by a gasoline engine. This engine also served as a generator for the siren, allowing it to operate independently of external power sources. While it was a good idea in concept, it was never popular. It had a very short production run, from 1952 until the mid 1950s.
Early Thunderbolt 2000s utilized the same early "jailbar" horns found on early 1000s between 1952 and 1953, while later models after 1954 did not. The 2000 was offered in 5 port single tone and (possibly) 4/5 port dual tone, and ran on a 6M blower (SN blower for 1952-1953 models).
Due to their unpopularity and lack of demand for gasoline powered sirens, only a few units remain. Two units are know to have been converted to electric motors, one being in Phoenix, Arizona at Fire Station 22, and the other at a school in Beebe, Arkansas. There is only a single known example of a original Thunderbolt 2000 with a gas engine that remains, which is located in Windsor Hills, California. It was converted to propane at some point, and is inactive like most of California's sirens. The unit in Beebe is active (albeit with a dead chopper motor at the current moment). Interestingly, Beebe's unit replaced a fried Whelen Vortex and is an ex-Phoenix unit.
The last remaining original Thunderbolt 2000 which still retains its gasoline engine. Located in Windsor Hills, CA.