The word is from the Latin funiculus, a diminutive of funis, "rope".
The basic principle of funicular operation is that two cars are attached to each other by a cable, which runs through a pulley at the top of the incline. Counterbalancing of the two cars, with one ascending and one descending the slope — especially when transporting similar loads, such as passengers — minimizes the energy needed to lift the ascending car.
The usual engineering practice is to splice the cable ends together thereby creating a continuous cable loop. The cars are attached equidistantly on the cable loop. The cable is driven by any means of winching at one end of the run, and held taut by a tensioning wheel at the other. Other sheave wheels are employed to guide the cable to and from the drive mechanism and the incline cars. Locomotion is created by alternately reversing the direction of the drive mechanism so that the cars switch positions on the incline, that is, one up and one down.
In many cases, such as on the Duquesne Incline in Pittsburgh, Pennsylvania, and most cliff railways in the UK, two parallel straight tracks are used. Separate platforms are provided for each vehicle, and there is sufficient space for the two cars to pass at the mid-point. The wheels of the cars are usually single-flanged, resembling those on standard railway vehicles.
Up until the 1890s, this four-railed parallel-track funicular was the normal configuration. The originator of the passing track was Prof. Thaddeus Lowe with his Mount Lowe Railway in Altadena, California (1893-1938). In an attempt to negotiate the steep climb of Mount Echo, Lowe was informed by his chief engineer David Macpherson that the grading required to accommodate the usual four rails would be extensive and costly. Most of the concern was caused by a large granite chasm that would require extensive backfilling and shoring. Overnight, Lowe came up with a configuration that employed three rails (now often just two), with four rails only at the dead center or passing section of the funicular.
Cars used with a two- or three-rail configuration have flanges on both sides of the outboard wheels, which keeps them aligned with the outer rail, thus holding each car in position. The inboard wheels are unflanged and ride on top of the opposite rail, thereby easily crossing over the rails at the passing track, and avoiding the need for switches and crossings.
The Angels Flight funicular in Los Angeles employs the three-rail configuration. Originally designed and constructed using a single cable attached at each end to the cars until its removal in 1969, Angels Flight was reinstalled using separate cables for each car powered from a geared mechanism. It was in fact this new mechanism which failed and caused the only accident in the railway's history.
Some funiculars have four rails, with the upper and lower sections interlaced and a passing section in the middle. These usually have a single platform at each station. The Hill Train at Legoland, Windsor is an example of this configuration.
The earliest such railways were water-driven, allowing barge traffic of canals to ascend and descend steep hills. An early example were the three inclined planes on the Tyrone Canal in County Tyrone that was in use as early as 1777. They were used primarily in the early 19th century, especially during the height of the canal-building era in the 1830s in the United States.
Such railways operated by allowing water in feeder canals at the top of the plane to drive a turbine, raising or lowering a canal barge along a steep slope. Along level sections, the railroads essentially operated as standard towpath canals, with the barges typically drawn by horse or mule.
Examples of hydropower inclined plane railroads in the United States included the Allegheny Portage Railroad, part of the Pennsylvania Main Line Canal, built in 1834 with ten planes as the first railroad across the Allegheny Mountains of Pennsylvania. Similarly, the Morris Canal in New Jersey connected the Delaware River with the Passaic River using 23 planes, as well as a series of locks along the gentler gradients.
One of the most famous funiculars of its time was the Great Incline of the Mount Lowe Railway in Altadena, California, designed by Andrew Smith Hallidie of San Francisco cable car fame. The Mount Lowe Railway combined its funicular, for raising passengers 2,800 feet (859 m) up the steep side of Mount Echo (elevation 3500 ft or 1067 m), with electric narrow-gauge trolley systems at each end (the Rubio Canyon line was standard-gauged after being acquired by Henry Huntington's Pacific Electric Railway). The Incline had three grade changes, starting with the lower end at 62% and easing to a 48% grade at the top. The cars were designed to adjust to the grade changes for the comfort of their passengers. A particular feature of the Great Incline was the use of only the three rails borne out of the need to reduce the width of the grading on the incline. An added advantage was the reduction of materials even though a complicated cable routing system was needed at the passing track.
The city of Valparaiso, Chile, uses them as an integral part of the urban transport service. There are more than 15, the oldest dating from 1883. Some of them are inside the historic quarter declared World Heritage by Unesco. They form the backbone of the transit system and are backed up by connecting buses.
Water-powered funiculars include the Lynton and Lynmouth Cliff Railway in North Devon, England; the CAT Funicular at the Centre for Alternative Technology in Gwynedd, Wales; the Nerobergbahn in Wiesbaden, Germany; and Bom Jesus funicular in Braga, Portugal (the oldest, still working, in the world).
Pittsburgh, Pennsylvania has two funiculars that travel between the top of the Mount Washington hillside to Station Square at the base of the mountain along the Monongahela River. It serves as a tourist attraction and mass transit system.
Naples, (Italy), is served by four funiculars. The Chiaia Funicular was built in 1889, then followed within two years by the Funicolare of Montesanto (Montesanto Funicular), and after some years by Central Funicular and Mergellina. But the most famous funicular in Naples was the Mount Vesuvius Funicular (1880-1944), the first railway track in the world built on an active volcano and destroyed various times by Vesuvius eruptions. Later partially modified to became rack railway in its last tract, it was definitively destroyed by eruption in 1944 and never built again. It is worldwide famous due to the fact that neapolitan song Funiculì Funiculà was dedicated to it.
The Johnstown Inclined Plane (built 1890), located in Johnstown, Pennsylvania in the United States, claims to be the world's steepest vehicular inclined plane. In addition to passengers, the Johnstown funicular is capable of carrying one automobile in each direction. Chattanooga, Tennessee is home to the funicular Lookout Mountain Incline Railway (built 1895) that travels from the base to the top of Lookout Mountain, which claims to be the steepest funicular in the world with a maximum grade of 72 degrees.
There is one in the Blue Mountains at Scenic World near Katoomba, Australia. Its center supports multiple tourist attractions such as the sky rail and cable car. The railway is on the old mining track and is 52 degrees (122%) at its steepest point. The operator (Scenic World) claims that this is the steepest funicular rail in the world.
Six Flags Magic Mountain in Valencia, California has a funicular which takes guests up the Mountain from an area near the park entrance to a station near the Ninja coaster entrance. It was simply called "Funicular" for many years, introducing thousands of people to the peculiar word, but is now known as the "Orient Express" to fit in with the Far Eastern theming at the top of the Mountain.