Express tube

An express tube is a form of tunnel found in Withmore City that provides ground vehicles with the ability to travel from one tier (or level) of the city to another. The tubes are constructed of primarily of plasteel and high tensile strength stainless steel. The structure spirals upwards from one tier to another, presenting a tunnel that rapidly climbs or descends as it banks. Foot traffic in the express tubes is forbidden, but it does not stop overly brave or stupid pedestrians from attempting to use them.