More than a night train
The economics of specialised rolling stock are a major obstacle to expanding overnight rail services. New interior designs that function effectively for both day and night travel could provide operational flexibility while improving the passenger experience, suggests Harald Buschbacher.
Given the high potential of modal shift from aviation to mitigate greenhouse gas emissions, offering more and longer direct trains could be an effective contribution to climate action.
But one of the major challenges to the widely touted expansion of overnight rail travel is the economics around the operation of increasingly specialised rolling stock, which limits their scope for deployment, capacity and revenue earning capability. The use of more flexible vehicles suitable for both day and night travel could offer advantages for both the passenger and operator.
The best solution from a purely operational perspective is to run overnight services using daytime rolling stock without sleeper or couchette accommodation, but that is the least attractive for potential passengers.
Passengers could benefit from more direct connections and less need to change trains, particularly if trains can run over longer distances than the city pairs typically linked by night trains today. Interchanging is a bigger burden for long-distance and cross-border travel than it is for local transport, as passengers have more luggage, are less familiar with the stations and can face more serious repercussions in terms of ticketing and seat reservations if a vital connection is missed.
For operators, the ability to use the same rolling stock for day and night services offers a more efficient use of capital. While some idle time is clearly needed for servicing and maintenance and to provide a buffer against delays, there is still potential to increase the average daily mileage compared to running separate fleets of night and day trains. However, this advantage must be balanced against the higher costs of specialist day-and-night stock, and also the lower seating density.
Interior concepts evolve
The make up of most European night trains remained broadly the same for decades, offering passengers a range of accommodation between the low-budget seating cars, four-berth to six-berth couchette as the most affordable flat sleeping option and one- or two-berth sleeper cabins — offering more comfort and privacy, including private bathrooms — as the most space-consuming and therefore most expensive.
Introduction of the next-generation ÖBB Nightjet trains, (Viaggio Next Level by Siemens Mobility) in December 2023 brought the ‘mini cabins’ for single travellers or couples at a similar price to a four-berth couchette car (Fig 1 & 2). While these provide more privacy at a reasonable passenger density, they make the night train rolling stock less suitable for use during daytime hours. In the mini cabins there is no legroom below the bed surface. Passengers can sit with their legs dangling outside the cabin or use a folding seat in the aisle. These are adequate for breakfasting before arrival, but not for using a laptop or for several hours of daytime travel. As the cabin entrances are stacked, there is no legroom for the upper occupant without impeding access to the lower cabin. Couchette compartments can be used in daytime mode with the bunks folded up to leave an upright seating position, but they also lack armrests and laptop tables.
A seven-car Nightjet set is 205 m long, carrying up to 260 passengers: 84 in mini cabins, 40 in two-berth sleeper cabins, 36 in four-berth couchettes, four in an accessible couchette compartment and 96 seated.[1]
Alternative train interiors suitable for day and night operation were investigated by the TANA research project, financed by the Austrian Ministry of Climate Action.[2]
The project team developed a design based on diagonally nested spaces, created out of lie-back seats and partitioning panels, giving a comfortable and ergonomic arrangement for single travellers and couples by both night and day. There was also an improved design for conventional compartments for up to four passengers.
A proposed 200 m double-deck trainset would be able to carry 317 passengers in daytime mode or 229 passengers at night, including 40 space-saving single-berth compartments. Only 28 of the 229 passengers would not have a horizontal sleeping position (Figs 3 and 4).
For comparison, the Alstom-built TGV 2N2 Euroduplex offers up to 556 seats.[3]
in the same length, while the DB ICE 3 neo single-deck trainset from Siemens Mobility has 439.[4]
In mid-2024, Škoda Group presented its ‘Sleep in Motion’ concept (Figs 5 and 6), based on a patented arrangement of nested single-berth compartments.[5]
Renderings suggested these could be deployed in a double-deck trainset, with two levels of compartments on the lower and one on the upper deck. However, this would require a 2 400 mm high lower deck, and probably an offset aisle position to ensure adequate height in the two walkways (Fig 7).
The ‘Sleep in Motion’ concept has been proposed as a pure night train without a multifunctional interior for use during daytime. Nevertheless, it could be adapted for day-and-night use, because the staggered access to the vertically stacked compartments on the lower deck would provide legroom for the upper compartment passengers, altering the positions of the ladder and the entrances to the upper and lower compartments (Fig 8).
Judging from published drawings[6], a 200 m long double-deck trainset could accommodate about 370 passengers in a horizontal sleeping position, most of them in single-berth compartments.
At around the same time, Berlin based start-up Luna Rail published another proposal for day-and-night train interiors (Fig 9).[7] This uses a high-density single cabin known as a ‘seat pod’, which is also based on a diagonal sleeping position, but with the foot end next to the window and the head end by the aisle. It is more nested vertically in order to achieve a high density in both day and night mode within the profile of refurbished single-deck coaches. There are also options for double or triple compartments, and single ‘hotel pod’ compartments offering more space. The beds in these compartments are arranged transversely to the direction of travel and make use of space below the central gangway.
A typical 200 m trainset could have four cars with the ‘seat pod’ interior, two cars with the ‘hotel pod’ arrangement, and a conventional couchette car with an accessible compartment, accommodating 366 passengers in total.
Fig 10 compares the seat/berth density of conventional day trains, conventional night trains and these day-and-night concepts, assuming that pairs of 200 m trainsets would be able to fit into a 420 m platform.
Operational disadvantages
Combined operation of day and night passenger services using the same rolling stock is not just a question of designing a suitable interior, there are also concerns about the operational and commercial feasibility.
Delay or cancellation of the night trains could impact on the punctuality and reliability of the daytime services. Cleaning, catering and changing the interiors takes more time than a short stop between the arrival of a night train and departure of the day train.
As the flexible trainsets would have fewer seats per unit of train length, that could result in insufficient capacity for some daytime services.
Commercially, it seems difficult to sell ‘part-route’ tickets for infrequent daytime trains far away from the home market, particularly if that route is served by other operators at regular intervals. Consecutive part-route bookings, where one passenger disembarks and another then uses the same seat, might require a high sales effort for a relatively poor yield. And it may require complex mutual acceptance of tickets and conditions, limiting the entrepreneurial freedom of the operator.
However, without consecutive part-route booking, night-and-day trains with a long route and journey time might tend to poor occupancy as many passengers would only take the train for a relatively short overnight leg.
Loco-hauled night trains are typically limited to a maximum of 200 to 230 km/h, making them slower than high speed trains. On some networks there may be further speed limits because of a high axleload or the inability to use high speed lines. This may lead to significantly longer journey time compared to an interchange between the night train and a high speed day train.
If the night train is restricted to conventional lines with freight trains and regional services, it may be difficult to obtain suitable train paths during the day. Journey times may be further extended by timetabling restrictions to fit around integrated regular-interval services running on the same tracks.
Finding feasible approaches
At first sight, these many obstacles led to scepticism or resignation about the idea of improving the popularity and efficiency of long-distance passenger services. However, closer consideration reveals a variety of conceivable options for night-and-day services, and not every obstacle applies for every variant.
Services could be created by a daytime extension of existing night train routes or longer routes could be introduced that overlap with conventional night trains running a shorter night-only route. Such overlapping might solve the problem of poor occupancy on the daytime section of a longer route, as the short-route passengers would take the night train instead of the through service.
Day-and-night trains might be able to replace some regular-interval services on the daytime section or run as an addition. Running them as additional trains overlapping with the day services might help to address any capacity and reliability issues.
The business case for the train operator may include the sale of consecutive part-route bookings on the daytime sections in order to reuse capacity freed up by other passengers using only the night section.
Combining the overlapping of short- and long-route night trains and minimising part-route bookings would reduce the effort needed for quick transformation between night and day modes, as well as sales and marketing far away from the home market.
The day-and-night rolling stock could be either loco-hauled trainsets, like nearly all night trains today, or a high speed EMU, as used in Japan and China. An EMU variant would be able to use dedicated high speed lines, shortening journey times and avoiding capacity conflicts with freight and regional services.
Fig 12 shows the relationship between variants and obstacles for day-and-night train operation as a decision tree. The most promising combination is highlighted by the green path.
This suggests that long-distance day-night trains should be run as an addition to existing night and day services, overlapping on their respective routes, and should not (at least initially) aim to sell consecutive part-route tickets as part of the core business case.
As a reasonable compromise between the advantages and disadvantages of consecutive part-route booking, empty seats could be released one or two stops after the previous passenger alighted, allowing sufficient time for cleaning and interior reconfiguration if necessary. As the train is not part of the daytime regular interval service there would be no need to comply with local fare conditions; empty seats could be made available to passengers without much promotion. This might appeal to passengers searching for less crowded alternatives during peak periods.
One particularly interesting application would be night-day-night routes with a journey time of 32 to 36 h. Such trains could achieve a relatively even occupancy without carrying local daytime traffic if the passengers gradually disembarking after the first night overlap with those gradually boarding to spend the second night on the train (Fig 11). Such a model can be found on other continents, but there are relatively few conceivable routes for such long journeys within Europe.
Use of high speed EMUs with a universal day-and-night interior instead of loco-hauled rolling stock would offer better journey times and easier pathing compared to loco-hauled night trains. It is generally not considered realistic to compare the average speed with a daytime passenger train because some high speed lines are closed for maintenance at night, and on others the fast night trains might conflict with freight trains using the route. In any case, a lower speed improves the comfort for sleeping passengers, at the trade-off of a longer overall journey time. Nevertheless, the ability to run at high speed during the night hours could contribute to better punctuality and reliability, as well as catering for any temporary capacity restrictions or diversionary routes.
Other deployment options
Apart from the core initial benefits of day-night trains for passengers and operators, such flexible rolling stock could potentially enable a more efficient fleet deployment without direct benefits for the passengers. The stock could be used to operate regular daytime services, but this creates an interdependence and rostering complexity, so it is not recommended. Running a larger number of day trains with day-and-night rolling stock would increase the risk of insufficient seat capacity.
Nevertheless, niche applications might include their use for sporadic day trains on top of the regular timetable, such as seasonal extras to tourist destinations or peripheral regions, running once or twice a day. Such trains are usually less interconnected to complex rolling stock logistics and might have lower capacity requirements. Seasonal extras could also be run at peak times to reduce the risk of overcrowding on regular services.
Using the day-night stock as backup trainsets could help to minimise cancellations in case of network disruption or failure of the regular vehicles. In case of a night train route with a travel time of significantly less than 12 h, on peak demand days both trainsets could be deployed on a daytime run between the two ends of the route (Fig 13).
While most night trains spend the whole time from arrival in the morning to departure in the evening in the sidings for cleaning, catering and maintenance, having a fleet of more flexible trainsets could help to cover a particular rolling stock shortage, leading to a better overall balance between reliability, peak capacity and the cost of holding reserve rolling stock fleets. From the business perspective, the advantage of these options is not so much the additional mileage potential, but a high rental paid by operators in urgent need of rolling stock or a high ticket yield for extra day trains during peak travel periods.
Harald Buschbacher works at Austrian rail innovation and standards body SCHIG, öffnet neues Fenster, having served as a timetable planner for national operator ÖBB. He has a PhD from Technische Universität Wien.
[1] Sebastian Wilken: Neuer Nightjet: Die wichtigsten Fragen und Antworten: https://zugpost.org/neuer-nightjet/, öffnet neues Fenster
[2] Bernhard Rüger et.al.: TANA - KundInnengerechte multifunktionale Zugkonzepte für den kombinierten Einsatz im Tag- und Nachtreisezugverkehr; Wien, 2024: https://projekte.ffg.at/anhang/67039002665a0_TANA_Ergebnisbericht.pdf, öffnet neues Fenster
[3] Wikipedia: TGV 2N2: https://fr.wikipedia.org/wiki/TGV_2N2, öffnet neues Fenster
[4] Wikipedia: DB-Baureihe 408: https://de.wikipedia.org/wiki/DB-Baureihe_408, öffnet neues Fenster
[5] Wilhelm Berbig: Liegen für einen Waggon: https://patentscope.wipo.int/search/en/detail.jsf?docId=AT434389761&_cid=P11-M3GYJC-16006-4, öffnet neues Fenster
[6] Deutscher Design Club e.V.: DDC Wettbewerb: Was ist gut 2023: Gewonnen: Sleep in Motion – Interiorkonzpet für Nachtzugwagen von Wilhelm Berbig: https://www.ddc.de/de/wettbewerb/was-ist-gut-2023/auszeichnungen/produkt/PRK-0169-sleep-in-motion.php, öffnet neues Fenster
[7] Luna-Rail website: https://luna-rail.com/, öffnet neues Fenster