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DLR Develops Lightweight Double-Decker Concept for Europe’s Future Night Trains
ALISA combines modular interiors, private cabins and flexible configurations, increasing passenger capacity by 40 percent without raising axle loads.
www.dlr.de
The German Aerospace Center (DLR), together with industrial partners TRICON, GETA, satek, and k+v, presented the ALISA double-decker passenger carriage concept at the InnoTrans trade fair in Berlin on 22 September 2026. The collaborative research initiative establishes an engineering architecture for European passenger rail services, integrating lightweight structural components and adaptable interior layouts to optimize vehicle payload capacity.
Industrial Context and Operational Challenges
Long-distance rolling stock operations face financial constraints due to low utilization rates, as conventional sleeper carriages remain idle during daytime schedules. Increasing passenger density typically results in higher structural mass, which raises axle loads, track degradation, and energy consumption. Addressing these operational parameters requires multi-partner cooperation to align vehicle dynamics, mechanical engineering, interior modularity, and lightweight manufacturing within standard European railway gauge limits.
Technical Architecture and Partner Roles
The consortium distributed systems engineering responsibilities across specialized domains:
- The DLR Institute of Vehicle Concepts conducted the primary mechanical design, structural topology optimization, and validation of mechatronic running gear systems.
- k+v Ingenieurgesellschaft collaborated on structural simulation, finite element modeling, and stress analysis of the load-bearing car body.
- TRICON formulated the interior ergonomics and conversion mechanisms to adapt sleeping berths into seated travel configurations.
- GETA developed the modular interior lining systems and structural integration components.
- satek engineered the compact modular sanitary facilities configured for double-decker envelopes.
The resulting train configuration comprises a three-car fixed-coupled double-decker unit measuring approximately 46 meters in length. Structural load distribution is achieved through multi-material design, utilizing aluminum face sheets bonded to aluminum or timber honeycomb cores. Cable routing and structural mountings are directly integrated into load-bearing extrusions. Continuous walk-through capability across both upper and lower decks is enabled by DLR-developed mechatronic single-wheel running gear, which eliminates continuous transverse wheelset axles.
Applications, Testing, and Operational Impact
Targeting intercity corridors, the ALISA configuration supports modular compartment layouts ranging from family suites and accessible cabins to dense seat configurations. Converting compartments between day and night profiles allows operators to deploy units across 24-hour revenue cycles, raising rolling stock utilization.
The concept was validated through structural simulation models, 1:1 scale interior mockups, and virtual reality evaluation tools. Compared to modern reference passenger vehicles, specifically the latest generation ÖBB Nightjet rolling stock, the lightweight configuration delivers a 40 percent increase in passenger carrying capacity without exceeding standard axle load thresholds.
Edited by Natania Lyngdoh, Induportals editor, assisted by AI.
www.dlr.com
