June 19, 2016 Leave a comment
When it comes to public transit systems, gondolas are sort of like Google Glass: they seem really cool, but no one really knows what to do with them or how to make them work. In the last decade or so they’ve been growing quickly, particularly in South America, and some places in the United States have been considering them as an alternative to more traditional forms of transit. While gondolas have certain advantages, they also come with a number of challenges, making their wider dissemination difficult. But in certain situations, such as those present in the small town of Johnstown, Pennsylvania, their unique advantages can provide better transportation service.
The first predecessor to the public transit gondola was an aerial tram system built in 1644 in Gdansk, Poland, which was used to move soil across a river to build fortifications. Early cable car systems were similarly used in mining operations, and the first people to use them for transport were probably miners. In 1893 the first aerial tram system exclusively for moving people was built in Hong Kong, and was used to transport workers to and from a mine. The first recreational cable car was built in 1907 at Mount Ulia near San Sebastian, Spain. After that development, the system was employed at other peaks throughout the alps, and from there became a mainstay at ski resorts around the world.
One of the earliest systems designed to be used for urban commuters was the Roosevelt Island Tramway, built in New York City in 1976. It was intended as a temporary connection between Roosevelt Island and Manhattan until a subway connection was completed, but due to delays in building the subway, it became a permanent fixture. While the Roosevelt Island Tramway and other aerial tram systems like it have a fairly high capacity and can move fairly quickly, they only have two passenger cabins (leading to less frequent service), their design only allows for two terminals and no intermediate stations, and their lines can’t turn. All of this adds up to their application as a form of urban transit being fairly limited.
The first true gondola public transit system, and to this day probably the most famous, is the Metrocable of Medellín, Colombia. Since 2004, Medellín has built three gondola lines (with two more in the works) that connect to the Metro system and run up into the barrios on the steep hillsides of the Aburra Valley. These barrios are so steep and so dense that regular buses simply couldn’t reach them, and residents were commuting over two hours by foot each way to work. Gondolas are able to travel over the community, rather than through it like a bus on a road would, so the development pattern below isn’t a problem. Using gondola technology rather than the older aerial trams also allows for intermediate stations and allows the line to turn, giving it much more flexibility both in its geometry and in how it serves the residents. Since it’s implementation, Metrocable has inspired dozens of similar systems in South America, Africa, Asia, and Europe, as documented by the Gondola Project.
Metrocable illustrates two situations where gondola public transit is particularly strong: extreme topography and irregular street networks. Gondolas aren’t for everyone; according to this paper by Baha Alshalalfeh, et al, they cost more to build than a standard bus system and have a much lower capacity than more expensive forms of transit. This is one reason why some large system proposals such as that in relatively flat and gridironed Austin may not work; for the same cost, you could build a tram system that could move about six times as many people.
Johnstown, in a number of ways, is not Austin. If you’ve heard of Johnstown at all, it’s probably because of the 1889 Johnstown Flood, the greatest single-day loss of civilian life in America before 9/11 and the source of it’s unfortunate moniker “Flood City” (though subsequent devastating floods in 1936 and 1977 didn’t help). Johnstown unfortunately has the perfect topography for severe flooding: steep mountainsides above and narrow river valleys with small pockets of flat, developable areas (many of them built on fill) below. Johnstown is divided into several somewhat discontinuous areas in the valleys along the Conemaugh and Stony Creek Rivers, as well as a few on the tops of the plateaus above. the discontinuous nature of the developable area in Johnstown makes navigating the city quite complicated.
If we were to design a gondola transit system for Johnstown, our first step would be to identify which areas are dense enough to support transit. We can do that by counting the number of housing units in a given block group and dividing that by the area of the block group.
What we can see is that there are many areas in Johnstown dense enough, according to the Victoria Transport Policy Institute, to support an occasional commuter form of transit, as well as a few (Downtown, Morrellville, and Moxham) that are dense enough to support some form of local bus. These should be the major hubs for our transit system.
The next step is to identify coverage. While there is a lot of variability when it comes to distances between gondola stops, in general they are about half a mile apart. We can calculate the center point for each block group and then measure a half mile radius from that center point.
From here we can take the block groups with the highest density and eliminate the other center points within a half mile radius from the list of potential gondola stops. As we do this, we arrive at the following system.
Alshalalfeh argued that gondola systems have similar capacity to bus transit, meaning that these lines could probably move the same amount of people that are currently using buses in this area quite easily. In addition, the ability to move in a straight line rather than following the circuitous routes that buses have to take saves a lot of time. For instance, a bus traveling from Oakhurst to downtown today would take about 18 minutes, while a standard MDG gondola moving at about 6 meters per second could do it in just 12. So while you are moving about the same amount of people, you are able to do it much faster in a gondola.
The entire system is about 5.8 miles long, and at a cost of about $8-16 million per mile, you’re looking at a total cost of $45-90 million for the entire project. While that is a lot more than you would pay for a bus system, it is cheaper than what you would pay for any other form of advanced transit. And while you would have a lot of land to purchase for most other forms of surface transit, you would only have to purchase the land for the stations and possibly an easement for the intermediate towers. Since Johnstown is a rustbelt city, it already has a lot of vacant or underutilized land which could be used to site stations.
While there are several technical reasons that a gondola system could work in Johnstown, there is also the intangible reason that it would just be really cool. Johnstown is a lovely little town tucked into some very dramatic scenery. There’s a reason that gondolas were used for recreational purposes before they were used as a means of transportation, and that is because the views from the gondolas are amazing. And while the scenes from the stops along the valley from Ferndale to Downtown would be great, the view as you go from Morrellville to Downtown would be breathtaking. If you maintain a straight line between the two stations, you would go over a rise that towers 400 feet above the valley floor. If the “Gringo Problem” that Medellín has experienced is any indication, people may travel to Johnstown just to ride the gondola over that peak.