TLDR: Aerial tramways are like cable cars that transport people or cargo. They use cables for support and propulsion. They are different from gondola lifts because they have lower capacity and longer wait times.

An aerial tramway, also known as an aerial tram or sky tram, is a type of transportation that uses cables to move cabins or cars. These trams are fixed onto the cables and cannot be detached during operation. They are commonly used in mountainous areas or for urban transport. Aerial tramways have one or two fixed cables for support and a moving cable for propulsion. They are different from gondola lifts because they have lower line capacities and longer wait times.

Aerial tramways consist of one or two fixed cables, a loop of cable for propulsion, and passenger or cargo cabins. The fixed cables provide support for the cabins, while the haulage rope, connected to a grip, propels the cabins. An electric motor drives the haulage rope, allowing the tramway to move back and forth between two end terminals. Aerial tramways are reversible systems, meaning the cabins shuttle between the terminals and change direction when they reach the end stations. This is different from gondola lifts, where the cabins are continuously circulating on a haul rope.

Some aerial tramways use a jig-back system, where one cabin is pulled down by a large electric motor, using the weight of the cabin to help pull the other cabin up. This system is also used in funicular railways. The cabins are usually situated at opposite ends of the cable loop, passing each other midway on the cable span. In some cases, aerial tramways have only one cabin, which is more suitable for systems with small elevation changes.

Aerial tramways have a long history, with the first known cable lift being built in 1644 in Gdańsk, Poland. They were initially used for mining operations, transporting ore from high mountains to lower mills. Over time, aerial tramways were adapted for moving people, especially in mountainous regions for sightseeing or skiing purposes. Today, they are also used for urban transport, such as the Roosevelt Island Tramway in New York City or the Portland Aerial Tram.

There have been several notable accidents involving aerial tramways, but safety measures have been implemented to prevent such incidents. Despite these accidents, aerial tramways continue to be a popular and efficient mode of transportation in various parts of the world.