Monorails, which were brought to Germany in the early 1900s, were expected to spread exponentially well into the 20th century. Unsurprisingly, the slow-tread train didn’t catch on in most cities, with only 254 miles (409 kilometers) laid down around the world today. However, with growing environmental concerns and financial cutbacks, the monorail seems to be returning to cities in years to come as a practical and efficient mode of urban transport.

In the next few years, it is expected that the number of monorail systems to be installed in major cities will double or even triple. Of the monorail systems installed in cities around the world, the majority are in Asia – specifically China and Japan. It is likely that the projected increase will be in Asia, parts of the Middle East and Latin America. Chinese automobile maker BYD announced in September of this year that it plans to install monorail systems in 20 major Chinese cities.


Figure comparing the daily ridership of monorails in different cities across the world (CC: Ghafripoor et al)

Canadian plane and train manufacturer Bombardier has similarly announced its plans to expand monorails to other parts of the world, starting with Cairo, Egypt. Earlier this summer, the company signed a memorandum of understanding with the Egyptian New Urban Communities Authority (NUCA) to construct a monorail between the working class neighborhood of Nasr City and the new capital city, which is 28 miles (45 kilometers) away from Cairo.

Although it has been around for more than 100 years, the monorail hasn’t caught on as a primary mode of transport in most cities. The monorail, which has been popularized in the U.S. at Disneyland and the Las Vegas Strip, is an electric-driven train that, as the name suggests, travels on one rail, similar to the metro or subway. Usually, monorails are integrated into road networks, but do not interfere with traffic like the tramway does, and are sometimes elevated from on the ground. Because it is common for monorails to also be elevated (i.e. not on street level), they have come to be associated with a style of train that travels on one track and is elevated.

In cities like Amman, Istanbul and San Francisco, the monorail is difficult to implement due to the hilly landscape. The latter two cities, however, do have some form of a tram that cross traffic and are not elevated from on the ground.

While the monorail remains an efficient and environmentally-friendly transport option, it isn’t necessarily the optimum solution for every city. From some cities, urban geography limits the feasibility of integrating a monorail. Cities that depend on trains or subway systems cannot always integrate monorail systems as efficiently because the cost of installing a monorail is usually higher than extending a metro or subway. Since monorails do not run alongside traffic, cities must fortify bridges, tunnels and other structures to allow the trains to run, which is not always financially feasible. For cities like Cairo and Tehran, for example, whose metro ridership is subsidized, installing a monorail will effectively cost city authorities more than maintaining the metro systems that already exist.


A table comparing the cost of building a metro versus that of a monorail (CC: Ghafripoor et al)

This financial constriction isn’t necessarily the case for all cities, however. For São Paolo in Brazil and Riyadh in Saudi Arabia, the monorail enables these cities to better their transport systems without needing to forgo budgets allocated for other infrastructural projects.

As monorail systems expand from Asia to elsewhere in the world, financial feasibility and urban integration are key to deciding whether the electric-driven train will truly make a comeback, and if it will be able to boost public transport systems in the process. Even when monorails are implemented, they might not work well with a city’s existing urban transport system. Sometimes, it is also a question of how well cities are able to maintain monorails or whether they are able to maintain them altogether – the Mumbai monorail that caught fire earlier this year being just one example.