Thanks! So far that site seems to be the best source of information I’ve been able to find (the Wikipedia article seems to mostly be a restated, trimmed down version of it) but there are a few other articles online I’m trying to vet for accuracy.
I’m especially interested in this quote:
“A fireless soda engine, together with evaporating apparatus, has been at work on the Aix la Chapelle-Burtscheid tramway for the last half year. In order to test the working capacity of this locomotive engine, and the consumption of fuel on a certain day, the Honigmann locomotive engine was put to work this day from 8:45 o’clock am till 8 o’clock pm, with a pause of three-quarters of an hour for the second quantity of soda lye. The engine was, therefore, at work for fully 10� hours, viz, 5� hours with the first quantity, and five with the second. The distance between Heinrichsalle and Wilhelmstrasse, where the engine performed the regular service, is 1 km, […] This distance was traversed sixty-four times, the total distance, including the journeys to the station, being 66 km.”
So it sounds like it ran for about five hours and traveled 33km on its load of caustic soda (I’m not sure at a glance which flavor chemical) and only took 45 minutes to refuel and come back up to temp.
And these were early designs, basically prototypes (though granted, the folks in that time making them probably knew a ton about steam locomotives). I imagine they could have been improved with time to study and refine the designs.
I’m not sure how well the boilers stood up to containing hot caustic stuff, but perhaps materials science has developed enough to help protect against that.
I’m writing and making visual art in the solarpunk genre, which tends to heavily emphasize trains and other public transit. But I want to broaden our options a bit beyond just electric trains. When I first heard about these, I felt like they’d mix super well with another invention of that time period, the mirrored solar concentrators used to run steam generators (some of the earliest solar power).
After all, one of the biggest disadvantages of the caustic soda locomotives was that it took more coal to dry the soda than to produce an equivalent amount steam directly with coal. But you don’t have to use coal. These 1800s mirrored dishes only require mirrors or polished metal and math to make (plus some simple motors and electronics to get them to follow the sun) and they could dry the soda for free. A lot of my focus is on less utopian, rebuilding societies, so trains and solar concentrators built with 1800s technology seems like a good place to start.
I’m going to start with a picture of a stop along the tracks for replenishing the soda in this style
plus a description. And I’m hoping to work them into a fiction story and a tabletop campaign.
As for the technical side, I’m not sure on whether they’ll be draining the diluted caustic soda and pouring in fresh, whether they’ll be drying it inside the locomotive’s boiler using superheated steam generated with a solar boiler besides the tracks, perhaps swapping locomotives to avoid delays, or even swapping boilers as someone on reddit suggested. If I go with swapping the soda, probably the boiler tank won’t actually be inside the dish, but nearby, with the steam from the dish heating it.
I hope that helps, I’m very new to this technology and am already trying to mix it with other stuff so we’ll see how it goes.