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rlkitterman — 1845 Parsey Pneumatic Locomotive Concept Model
#britain #engine #england #locomotive #modelrailroad #modelrailway #modeltrains #nrm #pneumatic #york #yorkshire #compressedair #conceptmodel #britishrailways #railroadmuseum #nationalrailwaymuseum #experimentalprototype #victorianera
Published: 2018-12-06 13:19:59 +0000 UTC; Views: 754; Favourites: 18; Downloads: 0
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Description
In 1839 and 1844, Arthur Parsey obtained patents for a compressed-air (pneumatic) locomotive, which he followed up on by building a scale model of a 2-2-2 engine in 1845 to advertise his concept to the Great Western Railway. Unlike the GWR's atmospheric railway, in which the "piston carriage" (not locomotive) carried a piston that fit into a pipe through which air was pumped to push the train, the pneumatic locomotive carried its compressed air supply aboard and fed it to the cylinders driving the wheels. The GWR does not seem to have ordered any full-size working prototypes, but Parsey's model has survived and is displayed at the National Railway Museum in York, England. Pneumatic locomotives have been rare apart from a few trams and mining engines, so like ammonia locomotives, caustic soda (alkaline) locomotives, and naphthalene (solid hydrocarbon mothball ingredient) locomotives they seem to have been one of the types that never entered wide use. From what little I have read, the main issues with pneumatic locomotives were the power consumed compressing the air, the heat produced during the compression, and the cooling effect of the compressed air being released from its container.Related content
Comments: 3
The heat generated during compression probably wasn't so much of a problem since in most systems the compression happens at stationary recharging points along the line at which the locomotive can be topped up. The real problem is the cooling of the compressed air expanding again, which can cause massive issues such as valves and pistons freezing, metal becoming brittle as it chills, and ice forming in places you don't want ice to form.
By far the most successful answer to this cooling issue were the Mekarski trams of the 1890's to early 1900's, which employed small gas-fired water tube boilers to inject small amounts of steam into the compressed air lines to keep them heated enough to avoid the freezing problem. This also allowed for the injection of lubrication oil at the same time. For a brief time around the Turn of the 20th Century the Mekarski trams dominated tramways throughout France; the double decker models in particular were once as much a symbol of Paris as the boulevards they ran along. Well regarded for their efficiency and relative quiet operation, far moreso than equivalent steam trams, their time in the sun was nonetheless surprisingly brief as by the mid-1900's electrification of tramways saw them all off, electric trams being, among their many advantages, easier to maintain. Sadly, none of the original Mekarski trams survived, but a group in Bern, Switzerland, the same that operates the city's historic steam tram on special occasions, has launched a project to build a new single decker Mekarski for the first time in over a century.
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... And I guess, coal was cheap! ... An elegant solution if working in an inflammable area!
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