For railroads in much of the U.S. and Canada, dealing with snow is a perennial problem. The earliest railroad plows were likely derived from agricultural plows, and were the first instance of a plow being pushed from behind rather than pulled by horses or oxen. In 1840, little more than a decade after the first steam engine plied American rails, Charles Lowbaert was granted a patent for a wedge, or "bucker," railroad plow. Like our model, that pioneering snowplow featured an inclined plane to bring the snow up off the rails and a pointed, triangular wedge to throw it to both sides of the track. Over time, railroad plows evolved into an arsenal of equipment ranging from engine-mounted blades to the ultimate snow-fighting weapon, the rotary snow plow.