Design and Operation of Autonomous Underground Freight Transportation Systems

Despite the increases in freight transportation demand, options for increasing capacity of the overground freight transportation infrastructure system are limited. This paper investigated the design and operation of an underground freight transportation (UFT) system that uses space below highways. Underground freight transportation is a class of automated transportation system in which individual vehicles carry freight through tunnels and pipelines between intermodal terminals. This paper presents attributes for schematic designs and operations for two UFT scenarios: a long-haul system which transports standard shipping containers between the Port of Houston and a terminal near Dallas, and a short-haul system which carries pallet-size freight between the Port of Houston and a satellite terminal near Houston. The appropriate design details were determined by the size of the freight, the types of vehicles and tunnels, and the propulsion system. In addition, operational attributes such as operating speed, headway, line capacity, and associated fleet sizes were addressed. Design sketches and operational equations presented in this paper are generally independent of the freight sizes and route lengths and this case study can be used as guidance for the design and operation of other freight tunnels and pipelines. (C) 2019 American Society of Civil Engineers.