Steam Engine - Advantages

Advantages

The strength of the steam engine for modern purposes is in its ability to convert heat from almost any source into mechanical work, unlike the internal combustion engine.

Similar advantages are found in a different type of external combustion engine, the Stirling engine, which can offer efficient power (with advanced regenerators and large radiators) at the cost of a much lower power-to-size/weight ratio than even modern steam engines with compact boilers. These Stirling engines are not commercially produced, although the concepts are promising.

Steam locomotives are especially advantageous at high elevations as they are not adversely affected by the lower atmospheric pressure. This was inadvertently discovered when steam locomotives operated at high altitudes in the mountains of South America were replaced by diesel-electric units of equivalent sea level power. These were quickly replaced by much more powerful locomotives capable of producing sufficient power at high altitude.

For road vehicles, steam propulsion has the advantage of having high torque from stationary, removing the need for a clutch and gearbox, though start-up time and sufficiently compact packaging remain a problem.

In Switzerland (Brienz Rothhorn) and Austria (Schafberg Bahn) new rack steam locomotives have proved very successful. They were designed based on a 1930s design of Swiss Locomotive and Machine Works (SLM) but with all of today's possible improvements like roller bearings, heat insulation, light-oil firing, improved inner streamlining, one-man-driving and so on. These resulted in 60 percent lower fuel consumption per passenger and massively reduced costs for maintenance and handling. Economics now are similar or better than with most advanced diesel or electric systems. Also a steam train with similar speed and capacity is 50 percent lighter than an electric or diesel train, thus, especially on rack railways, significantly reducing wear and tear on the track. Also, a new steam engine for a paddle steam ship on Lake Geneva, the Montreux, was designed and built, being the world's first full-size ship steam engine with an electronic remote control. The steam group of SLM in 2000 created a wholly owned company called DLM to design modern steam engines and steam locomotives.