Elevated String-Rail as a Novel Container Transportation Technology in European Ports: A Quay-Interface Simulation and Analytical Assessment of Ship Handling, Terminal Land Use and Road Traffic

Abstract

Elevated string-rail systems, in which unmanned electric vehicles run on steel wheels along a prestressed rail carried on slender supports, have been proposed as a way of moving containers between a quay and an inland terminal without using the road network. Their developers claim gains in ship handling speed, terminal land use and emissions at the same time, but none of these claims has been tested against measured port performance. This study assesses such a link at eight European container ports handling between 0.4 and 14.2 million TEU. The assessment combines two distinct components: a discrete-event simulation of the quay interface, calibrated against the Container Port Performance Index to within 1.5% of reported ship time at berth, and separate analytical calculations of required yard area, emissions and cost. The simulation covers the crane and horizontal-transport interface only; stacking, retrieval, reshuffling and yard-crane operations are outside its boundary. Internal model behaviour is benchmarked against independently published terminal operating figures, and the logic, inputs and scenario behaviour of the model were assessed by four specialists in container terminal operations. Because no published source gives the energy use of the vehicle, it is derived from physics, specifically from rolling and aerodynamic resistance, as 0.482 kWh per TEU-km. On an analytical capacity calculation, removing half of the road-borne inland volume would reduce required stacking area by 7.7 to 31.6%, equivalent to between 4.2 and 108.6 hectares of terminal area under a stated proportionality assumption, and a conditional comparison of emission factors gives a reduction of 60 to 97% on the diverted traffic alone. Avoided road haulage gives a positive annual balance at seven of the eight ports, with simple payback of 3.5 to 5 years at the five largest diverted flows. The benefit depends on how much of a port’s traffic actually leaves by road: gateway ports with heavy road use gain most, while a transhipment hub such as Piraeus gains least despite its size. Ship handling improves by at most 3.8%, well below the 5 to 10% claimed, and the improvement comes from avoiding the drive across the yard rather than from a faster crane cycle. Measured against the price of carbon, the investment is poor value, but measured against the cost of road haulage, it is not, which suggests such links should be planned as land and traffic infrastructure rather than as an emissions measure.