We have spent the last several weeks looking at some of the benefits of public transportation, according to its advocates. This week we shift gears and look at some of the challenges that public transportation faces when the topic is raised.

We look at the challenges around substantial initial costs, long construction times, and the risk of low utilization once it is built.

We have looked at most of the well-recognized modes of public transportation, but what about some of the lesser utilized ones? This week we spend some time looking at lesser known modes of public transportation, and we look at how they are utilized around the world by different cities and communities.

We look at monorails, and their ability to offer a medium-level rail option without the footprint of laying tracks on the ground. We look at aerial gondolas and how they are able to connect neighborhoods in areas with difficult topography, and we look at maglev trains, and how they can offer high speed rail using newer technology.

We continue our conversation around public transportation, this week focusing on heavy rail. Heavy rail is different from light rail mainly in scale and capacity. Heavy rail cars are larger, and heavy rail trains often include more cars than light rail, meaning they can carry many more passengers at a time.

Proponents of heavy rail often see it as a foundation of a larger public transit system, carrying millions of passengers every day between major hubs, with lighter public transit lines, like buses and trolleys, carrying passengers the last mile or two to their final destination.