An illustration of a horse-drawn street car. The first passenger services in the world were started by the Oystermouth Railway in Wales, using specially designed carriages on an existing tram line built for horse-drawn freight dandies. Fare-paying passengers were carried on a line between Oystermouth, Mumbles and Swansea docks from 1807. Other forms of public transit developed out of the early omnibus that first ran on public streets in the 1820s. These were local versions of the stagecoach lines, and picked up and dropped off passengers on a regular route, without the need to be pre-hired. Horsecars on tram lines were an improvement over the omnibus as the low rolling resistance of metal wheels on iron or steel rails, (usually grooved from 1852 on), allowed the animals to haul a greater load for a given effort than the omnibus. The horse-drawn streetcar combined the low cost, flexibility, and safety of animal power with the efficiency, smoothness, and all-weather capability of a rail right-of-way.