Optimising the configuration of a double-decker sleeping car from Germany to the Mediterranean - squaring the circle

Abstract

The revitalization of night train services aims to offer a sustainable alternative to air travel on routes between 500 and 2000 km. However, high operating costs make ticket prices uncompetitive compared to low-cost airlines and high-speed day trains, resulting in the discontinuation of several services in Europe over the past 15 years. Challenges persist, including limited passenger capacity, large space requirements per passenger, and lack of seat turnover. Furthermore, the constraints of the G1 gauge limit international services, putting night trains in central Europe at a disadvantage compared to the American Superliner or the Finnish VR Ny, as well as other modes of transportation. This paper explores early-stage design strategies to improve the economic viability and efficiency of double-decker sleeping cars. Findings from Project “AliSa” identify critical design trade-offs and technical constraints. Desk research and CAD analyses reveal that accommodating two double cabins on both the upper and lower decks within the G1-profile is not feasible, as seen with the Superliner model. One alternative is to mphasize reclining armchair seating, which is less affected by height restrictions and offers greater flexibility. Norske tog’s survey indicates positive passenger attitudes towards this option, particularly when paired with private cabins to enhance privacy. Additionally, shorter but wider carriages improve spatial efficiency and comfort. A novel configuration is proposed to maximize capacity while adapting to demand variations. Some armchairs are reserved for the entire journey, while others allow seat turnover. This setup incorporates adaptive lighting and modular partitions to balance privacy with occupancy efficiency. A linear programming simulation using demand scenarios and different ticket prices optimizes the upper deck configuration, combining two-person cabins, overnight armchairs, and turnover armchairs. Results indicate that turnover armchairs are more profitable in high-demand scenarios, while night armchairs gain relevance in lower-demand situations.