The Impulsoria: A Horse Powered Railway Engine

Do you want to run a railway, but can't afford a steam engine? Do you have 4 horses? Well, have we got a solution for you!

The Impulsoria was a locomotive constructed in 1850 that was powered by horses on a treadmill following a design by Clemente Masserano. The locomotive came at a time when steam engines had been state-of-the-art technology for at least two decades, but when some railways still used horse power, and there was at least some debate as to whether the technology of steam was worth the cost. Thus, the locomotive was sort of a hybrid design that could satisfy these customers, at least that was the idea behind the patent.

An excerpt from The Engineer and the Machinist describes the Impulsoria in depth, "An ingenious way to use animal power for railway transport—so as to avoid the high costs of locomotives—has recently been invented in Italy and demonstrated on the South Western Railway. It involves placing animals inside a type of coach called an impulsoria. Inside this coach, the animals walk in place on a special moving platform. As they walk, they stay in the same spot, but the platform moves backward, essentially transmitting their walking motion to the wheels of the vehicle. 

The transmission system is quite simple, using the animals' walking effort and their weight to generate power. The animal walks on a flat, smooth, moving surface—so smooth that the animal doesn't actually move forward, but instead causes the platform to move backward. This motion turns a wheel with a pulley, which pulls a rope that drives the axle of the coach's wheels. By changing the pulley sizes, different speeds can be achieved.

The animals walk at their normal pace, yet the coach can reach speeds up to 60 miles per hour [though this was likely an exaggeration], without tiring the animals more than usual. The animals remain inside the impulsoria, much like being in a covered room, protected from the elements.

The idea of using extra power from the animals more efficiently has been considered before and tried in England, France, and Italy—but without success until now. The new version, invented by Signor Clemente Masserano of Pinerolo, Piedmont, has now been brought from Italy to England. It’s currently at the Nine Elms station of the South Western Railway, where it’s being tested on the tracks. Only two horses are needed, and the system has performed well using the patented pedivella (a foot-crank or similar mechanism). Over 80 carriages have already been adapted for this method, where the animals stay at the station while the train is pulled out using their power through a long rope system." (The Engineer and the Machinist, 184)

The locomotive undertook trials in London in 1850 and was exhibited at The Great Exhibition in 1851. It was a 2-2-0 Engine design. The Impulsoria "was said to be able to pull 30 wagons up an incline." (Everything Explained)

Impulsoria Illustration. British Newspaper Archive

A maximum of four horses could be used in the design. In The South Western Railway: its mechanical history and background, it was noted that the design could be used with only two horses, but despite our original claim that the illustrations for the design mostly consisted of two horse operations, it seems only four-horse illustrations survive today. 

One illustration showing four horses.

Compared to our typical understanding of horse-powered railways, and iron horses, this design is strange to say the least, but in theory, it could have ran more efficiently than a steam locomotive at the time, and was projected to be able to reach a maximum speed of 20 mph. 

Other than one prototype unit, however, the locomotive was never produced. By 1850, steam was clearly king, and any horse-powered railways outside of streetcar operations were on the way out. Thus, the Impulsoria became nothing more than a strange curiosity of an early railway engine.

Thanks as always for reading!