The slot in the road: Manhattan's forgotten underground electric trolley system

Due to city regulations, overhead wires, and electrical poles were not permitted in the borough of Manhattan, New York, USA. The unintended consequence of this ban was prohibiting conventional electric overhead trolleys from the streets of New York City. The only mode of public transportation allowed in the early 1890s, was either horse-drawn streetcars or cable-drawn cars, both expensive to operate and socially and technically undesirable. This ban would become an opportunity for entrepreneurs to find a solution to this problem with the Slot in the Road. The slot, or electric conduit, was Manhattan’s unique mass transit system launched by a very progressive company over a century ago. The conduit system was used to propel streetcars, or trolley cars, by electricity coming from a source located underground, between the tracks, instead of overhead wires. In traction terminology, this type of traction is a ‘subsurface double conductor system with metallic return’. The electric conduit was very different than the third rail for subways. It was the Metropolitan Street Railway Company that first introduced safe and comfortable transportation for travelers in Manhattan. This service was rendered on surface roads with the electric conduit, a service which continuing for years while new subways and elevated lines were being built. Metropolitan was the first to run a dependable mass transit system and promote travel by free interchange of transfers. It also manned special streetcars waiting on sidetracks to serve the crowds leaving Manhattan’s theater district. The electric conduit remained in service for nearly 40 years. By 1936, the last electric car had been replaced by buses burning diesel fuel. Years later, car tracks were removed and streets were repaved.