The ALISA night train concept, presented at InnoTrans 2026 in Berlin, could carry 40% more passengers than ÖBB’s latest Nightjet at the same axle load, DLR says.

ALISA night train concept with double-deck carriages crossing a viaduct at sunset
The ALISA double-deck night train concept shown on a viaduct. Image: ALISA-Projekt / Tricon.

The German Aerospace Center (DLR) presented the concept on 22 September together with its project partners. Its Institute of Vehicle Concepts developed ALISA with TRICON, GETA, satek and k+v, with funding from Germany’s Federal Ministry for Economic Affairs and Energy (BMWE). The name stands for Angebotsdifferenziertes, leichtes und innovatives Schlafwagenkonzept, rendered in English as a service-differentiated, lightweight and innovative sleeping car concept. At its core is a unit of three permanently coupled double-deck carriages about 46 metres long.

Lightweight structure behind the capacity claim

A second deck, more passengers and higher comfort standards can all push a carriage’s weight up sharply. That is why DLR concentrated on keeping the vehicle as light as possible. Its researchers optimised the carriage body to spread and absorb loads efficiently, reinforcing the areas under the heaviest stress and slimming down those that carry less. They also examined how cable ducts and interior fittings could be built straight into the load-bearing structure, saving weight without taking usable space. Multi-material construction brought further savings, including sandwich panels that pair an aluminium skin with a core of wood or aluminium honeycomb. DLR developed the structure together with k+v Ingenieurgesellschaft.

ALISA night train interior with seats, cabins and a continuous upper-deck aisle
The ALISA night train interior with seating, cabin doors and a continuous aisle. Image: ALISA-Projekt / Tricon.

Nicolai Schmauder, DLR’s project lead, described what the approach delivers:

“With our consistent lightweight-construction approach, we can increase passenger capacity by 40 percent with no increase in axle load, while passengers don’t have to compromise on comfort or privacy.”

He said the reference point was the latest-generation Nightjet run by Austrian Federal Railways (ÖBB). The release gives no absolute passenger figure for an ALISA unit and does not explain how the comparison was calculated.

Siemens Mobility, which builds the train, set out its layout in 2022. Each seven-car set has two sleeping cars, three couchette cars and two seating cars, carrying a maximum of 254 passengers. ÖBB gained privacy by lowering occupancy to two people per sleeping compartment and four per couchette compartment, and by adding mini cabins for solo travellers.

Three-car units that can be coupled to match demand

Passengers can walk through both decks along the whole unit. DLR credits this extra space, and the better accessibility that comes with it, to a mechatronic single-wheel rail running gear that it developed and tested in-house. Several units can be coupled together, so an operator could adjust train length to the route, the level of demand and the season.

ALISA sleeper cabin with stacked beds, pillows, tables and a large window
An ALISA sleeper cabin with stacked beds, tables and a large window. Image: ALISA-Projekt / Tricon.

The modular idea continues inside. Standardised segments allow different interior layouts without designing a new carriage body for each variant. The planned range runs from ordinary seats and reclining sleeper chairs to private single or double cabins. Larger compartments cater for families and for travellers with reduced mobility. GETA contributed its expertise in rail interiors and satek its experience with sanitary facilities.

ALISA concept and latest-generation Nightjet compared
Feature ALISA concept Latest-generation Nightjet
Formation Three permanently coupled double-deck carriages, about 46 metres long; several units can be coupled together Seven cars: two sleeping, three couchette and two seating cars
Published passenger capacity No absolute figure published. DLR cites 40% more capacity than Nightjet with no increase in axle load, without saying whether this applies per car, per unit or per train Up to 254 passengers per seven-car train
Private sleeping space Private single or double cabins Two-person sleeping compartments with their own toilet and shower; mini cabins for solo travellers
Other accommodation Seats and reclining sleeper chairs Four-person couchette compartments; seating cars
Families and reduced mobility Larger compartments for families and for travellers with reduced mobility One accessible couchette compartment and a bathroom with low-floor entry in each train
Daytime use Sleeper cabins convert into seating for day services Not described in the 2022 release

The two formations differ in number of cars, so the table is not a like-for-like comparison, and ALISA’s capacity cannot be derived from Nightjet’s 254 passengers. ALISA so far has only DLR’s relative figure of 40% more capacity. ALISA is a research concept, not a vehicle in service. Sources: DLR, 22 September 2026; Siemens Mobility, 6 September 2022.

Sleeper cabins that convert to daytime seating

DLR says demand for night trains in European long-distance travel is rising. It links the growth to climate and environmental concerns and to the chance to spend the journey more comfortably and productively than by car or plane. To run economically, rolling stock has to move the largest possible number of passengers and be used often. Traditional sleeper and couchette cars were designed mainly for night use and usually stand idle during the day.

The interior concept from design agency TRICON uses folding and conversion mechanisms so that sleeper cabins can serve as seating areas by day. The same train could then run both overnight and daytime services. In an August post introducing the project, TRICON wrote that night trains are popular but seldom profitable, citing ageing fleets, limited capacity and high running costs as key reasons.

ALISA mock-ups on show at InnoTrans until 25 September

Until 25 September, the project team is presenting the concept at InnoTrans with a 1:10 model of the complete three-car train. Visitors can also walk through full-size sections of chosen compartments and use a VR application that shows the interior and carriage body. Messe Berlin, the organiser, lists ALISA among several night-train concepts at this year’s fair, with the mock-ups housed in a tent outside the South Entrance.

ALISA remains a research concept. The DLR release names no operator, order or date for a vehicle in service.