The Widowmak’r uses a two cylinder (or compound) engine for quick acceleration and power and a steam turbine as a second stage for sustained speed and long distances. Like most steam powered vehicles and devices, it is powered by Moriarty H202 (Hydrogen Peroxide) steam generators which use a catalyst to cause the H202 to boil rather than a boiler to produce power. The formula of the catalyst is a secret of Moriarty Chemical, which is the exclusive producer and seller of the material.
The Widowmak’r was designed and built by Sherlock Holmes; its engines come from military stock vehicles produced for the British military by Moriarty Motors. The Widowmak’r is most probably the fastest land vehicle of its time.
The Gatling gun, also military stock produced by The Gatling Co., fires 300 rounds per minute. Instead of being driven by a hand crank, as was common, the eight barrels turn and fire using the kick-back for the previous round (aka Recoil-Operated). The ammunition is a smaller caliber .303 Lee-Metford bullet of lead encased (jacketed) in copper to improve accuracy (lead tends to warp its shape when fired, distorting accuracy).