A horsecar is a transit vehicle that runs on iron or steel rails and is pulled by a horse or mule. Horsecars first appeared in the first half of the nineteenth century and rapidly replaced omnibuses, the then dominant form of public transportation in cities and towns. The low rolling resistance of their metal wheels on the metal rails allowed horses to haul greater loads than the omnibuses, which ran on cobblestone, dirt or mud roads, and to provide higher speeds. It also resulted in a smoother ride and thus reduced vehicle maintenance.
Horsecars came into widespread use in cities around the world during the second half of the nineteenth century. However, serious problems remained with the use of horses to pull transit vehicles. One was that a large amount of manure was produced, which was not only unpleasant but also a health hazard. Horsecar systems were also expensive to operate, not only because of the large volumes of hay needed to feed the hard-working horses but also because of the cost of collecting, storing, and disposing of the manure. In addition, many horses were required because each horse could only work a few hours per day, and the working lives of the horses were typically very short at only around two years.
Thus, there were attempts to develop improved forms of motive power. One was to use small steam locomotives to haul the rail transit vehicles. However, steam locomotives had the serious disadvantage of occasional deadly boiler explosions. Cable cars, which were invented in 1873 and which use constantly moving metal cables installed in slots under the streets between the rails to pull the vehicles, solved many of the problems of horse-drawn vehicles and soon began to replace them on many of the more heavily used transit systems around the world.