Tragedy has struck Lisbon’s funicular railway. Transport expert explains how these old-fashioned trains work

Some 15 people have died after the Gloria funicular railway car in Lisbon, Portugal, derailed and crashed on Wednesday local time.

Emergency services have also confirmed that more than 18 people were also injured, five of them seriously, in the tragedy, which occurred at the start of the evening rush hour.

It follows another accident on the same line in May 2018, when one of the cars derailed due to flaws in the maintenance of its wheels. No one was killed in that incident.

The exact cause of the most recent accident is not yet known. Witnesses have reported that the yellow-and-white tram appeared out of control as it sped downhill, before derailing as it rounded a bend and crashing into a building. Photos of the aftermath show a crumpled heap of cables and steel.

These cable car–like transport systems are rare relics of the 19th century, found in only a few very hilly places around the world. So how do they work? And why are they still in use?

How do funicular railways work?

Trains and trams typically only work on flat terrain. That’s because their steel wheels can’t get enough traction on steel rails on steep hills. As a workaround, railroad engineers often build tunnels through steep mountainsides.

Funicular railways, however, can go up very steep hills.

They usually feature two counterbalanced cars that are attached via a haulage cable.

As one car descends, it helps pull the ascending car up the hillside. The weight of the ascending car also prevents the descending one from careening out of control. Some now have electric motors to help power them and some are able to engage a one-way mechanical drive just for steep hills.

Even though funicular systems are typically quite slow and clunky, they are still popular with both tourists and residents in the places where they’re found.

Where are they found?

The Gloria funicular railway line in Lisbon opened in 1885. One of three funicular lines in Lisbon, it connects the city’s downtown area with the Bairro Alto (Upper Quarter).

But there are other examples of these transport relics around the world.

Switzerland has several funicular railways. The most notable is the Stoosbahn—the steepest funicular in the world. It covers a total ascent of around 744 meters, reaching a gradient of 47 degrees. It is a very popular tourist trip.

In Hong Kong, the Peak Tram is a funicular railway that has operated since 1888 and takes people to near the top of Hong Kong Island.

Last year, there was also some discussion about installing a new funicular railway system in the Blue Mountains in New South Wales, Australia, that would travel 14 meters every second.

The rise of trackless trams

Funicular railways still serve a purpose for people living in—or visiting—steep areas where they’re found. However, newer technology means more conventional forms of rail transport are now far less limited in traveling up and down hills.

For example, trackless trams are kind of a combination between a tram and a bus. They use GPS and digital sensors to move precisely along an invisible track and have rubber wheels, enabling them to ascend gradients of up to 15%. However, these have not yet been built for steeper hills.

I have enjoyed riding such funicular trams in a range of hilly cities, but this crash is likely to take the shine off the tourist experience. It’s about time we had a 21st-century option that is clearly safer.

This article is republished from The Conversation under a Creative Commons license. Read the original article.