What is a funicular railway?

A railway cable going through a mountain. — A funicular uses the technology of an elevator and the technology of a railroad. Alex Saurel / Getty Images

A funicular railway uses the technology of an elevator (a cable pulling a car up) and the technology of a railroad (a car on a track). Devised in the 15th century as a way of getting people and things up steep hillsides, the funicular now is more likely to carry skiers to the top of a mountain. In the United States, they are often called an incline railway, or a double inclined elevator.

A conventional train could never travel up such a steep incline because the steel train wheels don't have enough traction against steel rails. Trains that do climb mountains go up tracks that spiral around the mountain or go through many switchbacks.

You might be wondering then, why not build a train with rubber tires instead? They might have enough traction to make it up a steep slope. The reason trains have steel wheels and tracks is to minimize rolling resistance.

This is a force that tends to slow wheeled vehicles down. It comes from the weight of the vehicle squishing the tires. Even with rubber tires, however, it would be tough to get enough traction on steep slopes.

Funicular Railways

The cable railway conquers these problems in a very elegant way. First, the car is pulled up the mountain by a cable, which means that traction is no longer an issue. The wheels just guide the car up the mountain. They don't provide any of the pulling power.

But the true genius of the double inclined elevator is that it uses two cars at the same time, one on each side of the top pulley. At any one time one car is balancing the weight of the other.

The descending car's weight helps pull the ascending car up the mountain, and the ascending train keeps the speed of the descending car from going out of control.

There is still a motor powering the pulley but it only has to provide enough force to overcome the difference in weight between the two cars (the weight of the passengers) and to overcome the friction in the system.

The Kitzstenhorn Cable Car

At the Kitzsteinhorn glacier in Austria where the accident happened Nov. 11, 2000, two cars carry many visitors up and down the mountain on a single cable that forms a loop around a pulley at the top of the mountain, and one at the bottom.

The Kitzsteinhorn cable car runs on electricity, which is supplied from a power station at the top of the mountain. An electric motor at the top keeps the cable moving. There is a passive pulley at the bottom of the mountain that provides tension to the loop of cable.

The Austrian funicular has a single set of tracks going up the whole mountain except for a small section in the middle where it splits into a double track. This is where the two cars pass each other.

The Montmartre Funicular

Situated in the heart of Paris, the Montmartre funicular is not just a means of transportation but also a piece of the city's rich historical tapestry. While it offers a pragmatic solution for those wishing to ascend the steep hill without exertion, it also provides scenic passage through one of the most iconic neighborhoods in the city.

The popular tourist attraction was opened in 1990, and has seen multiple redesigns and renovations. The electric cable railway serves as a public transport alternative, and serves over 2-million passengers each year.

Building a Double Inclined Elevator

The concept of a double inclined elevator, commonly known as a funicular railway, revolves around constructing an inclined transportation system that utilizes two counterbalanced cars. These cars move in opposite directions on a shared track system, with one ascending while the other descends, thus providing balance and conserving energy. Here's a more detailed exploration:

Physical Setting

Building such a railway system is no simple task. Typically, these railways are found on steep terrains such as mountainsides or hills. In the case of Kitzsteinhorn, which is 10,499 feet (3,200 meters) tall, the tunnel through which the funicular travels is even longer than the mountain's height, measuring 11,483 feet (3,500 meters).

This presents a range of engineering challenges:

Stability and foundation: Constructing on steep inclines necessitates careful geological surveys to ensure the stability of the ground. The foundation must be able to bear the weight of the tracks, the cars, and the passengers, all while withstanding environmental factors like wind, rain, and snow.
Track laying: The tracks have to be meticulously laid so that they are parallel and at a consistent gradient. Any deviation can result in imbalances, which can be dangerous when dealing with the high speeds and pressures of funicular travel.
Tunneling: When the railway needs to pass through a mountain, like in the case of Kitzsteinhorn, tunneling becomes an essential component. Tunneling at such lengths requires sophisticated machinery and precise planning to ensure safety and functionality.

Underground Funiculars

While many funiculars offer scenic views on mountainsides, they also serve practical purposes below ground. These underground incline railways have been constructed for a variety of reasons:

Mining: One of the earliest applications of funiculars was in mines. Deep underground mines required an efficient way to transport workers and ore to and from the surface. Funiculars provided a faster, more energy-efficient method compared to traditional hoisting methods.
Cave exploration: Some of the world's largest and deepest caves have incorporated funicular systems. These railways help researchers and tourists descend safely and efficiently into the depths of the earth.
Urban transportation: In cities built on hilly or mountainous terrains, funiculars can serve as a mode of public transport. They efficiently connect higher altitudes with lower regions, aiding in the reduction of traffic congestion and offering a unique commuting experience.

Funicular railways truly are impressive feats of engineering. Whether it's scaling great heights, delving deep underground, or facilitating urban movement, the funicular remains a testament to human ingenuity and innovation.

Here are some interesting links:

How Force, Power, Torque and Energy Work
How a Block and Tackle Works
Funimag, a magazine devoted to funicular railways
Angel's Flight, a funicular in Los Angeles
Vesuvius Funicular