Biocoal - the future of steam?

Milwaukee County Zoo railroad’s 15-inch gauge 4-6-2 No. 1924 was used for the CSR’s initial tests of biocoal on June 11/12. DAVIDSON WARD


Firemen could end up with green fingers rather than blackened ones, with the first ever trials of a steam locomotive burning the carbon-neutral fuel of torrefied biomass - or ‘biocoal’.

In the United States, the Coalition for Sustainable Rail (CSR) - a not-for-profit Minnesota-based group that aims to restore Atchison, Topeka & Santa Fe 4‑6‑4 No. 3463 to run on biofuel - has started off on a smaller scale. Fifteen-inch gauge 4‑6‑2 ‘Pacific’ No. 1924, one of two locomotives on the mile-long Milwaukee County Zoo railroad, was used for controlled tests on June 11/12 in conjunction with the Natural Resources Research Institute.

Fitted with instruments to measure the temperatures of the firebed, combustion space and exhaust gases, No. 1924 was fired with coal on the Saturday and ‘biocoal’ on the Sunday, the latter fuel donated by New Biomass Energy.

Initial results indicated that the biomass burned at a similar temperature to the zoo’s coal, but that its taller flames would help to even out stresses in the firebox.

The smaller size of the biomass pellets meant that the locomotive’s grate had to be modified with stainless steel mesh, and only a thin firebed could be maintained. This made it necessary to fire the engine more often - and the free-flowing pellets (intended for mechanical stoker firing) also proved difficult to keep on the shovel blade.

However, CSR President Davidson Ward said: “The fuel can be manufactured to any practical size specification. We will be running a second series of trials with larger ‘pucks’ of fuel in a few months’ time.”

With the principle proved, CSR has opened discussions for further tests on standard gauge locomotives - pointing the way to its ultimate aims for No. 3463. As reported in SR403, it plans to rebuild the 1937-built Baldwin locomotive to not only prove the clean fuel technology, but to make a 130mph attempt on the world steam speed record.

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