Soda, pop, cola, it’s the fizzy sugary drink we all know and love. Back in the 1800s, the soda fountain was the place to socialize. Soda was the foundation to social life back then, and it also happened to be the fuel that powered trains.
Well, kind of.
Trains that ran on soda were called the soda locomotives, understandably. Though, while soda pop certainly was a hot commodity then and still is, and some trains in the 1800s did run on soda, the two sodas aren’t really the same.
The train was essentially just a steam engine that utilize chemical reactions from soda to heat up the water into steam, rather than burning coal. These types of trains weren’t the most common, but they did exist as a way to run a fire-less steam engine.
Inside the boiler of these trains was massive amounts of caustic soda, or sodium hydroxide. Water was then added to the soda, which would create a massive exothermic reaction, instantly boiling the water into steam and powering the train.
Just like a typical steam engine, the steam produced from the boiler is what moves the pistons of the engine, so mechanically soda trains worked almost identically to coal trains. The biggest benefit of soda trains though was that they were completely smoke and exhaust less. They were also pretty silent compared to coal trains.
The trains would run for several hours at a time on one full load of soda, but eventually the reaction would slow and the water would stop being boiled into steam. At this point, the train would be reloaded at a station. Engineers would inject superheated steam to boil off the water, leaving only caustic soda, they’d then add more soda to top everything off, add more water, and the soda train was ready to keep on chugging.
These unique trains that ran on soda were first invented in 1880 by a German chemist by the name of Moritz Honigmann. His fireless trains were first used in Berlin and other German cities, then making their way to Philadelphia in the US. However, this would be the only US city to adopt the technology for any period.
There were a few problems with the soda trains, mostly in terms of efficiency, but also that if mismanaged, they could do this thing where they just, well, exploded shrapnel, caustic soda, and superheated steam everywhere. No biggie.
Researchers found that the soda was only 60 percent as effective as coal per unit, and while there were benefits like no exhaust and cheaper refueling, the risk of explosion and the hurdles of adopting a new technology stood in the way of soda train adoption.
While steam locomotives continued on, soda trains slowly died out, with coal moving back into it’s lone position as the best fuel for steam trains. So, that’s the story of soda pop trains, how they almost overtook coal trains, but ultimately fell out of favor due to lower efficiency and higher chance of spontaneous explosion.