This project explores the prospects for interior design in a dual purpose train that can run both day and night for improved utilization and comfort.

Contemporary trains are categorized as either exclusively for daytime or nighttime use. Their interiors limit them to specific temporal contexts. For instance, in daytime trains, passengers are confined to sitting positions and cannot lie flat, resulting in suboptimal sleeping comfort. Thereby the appeal of such trains for night (long distance) travel is reduced. Conversely, in existing night trains, while passengers can lie flat, the fixed layout featuring compartments and beds makes the capacity of the train too low for daytime use. Moreover, night trains face strong competition from aviation, rendering their utilization challenging.

A solution to this problem involves designing a train interior that serves the dual purpose of accommodating both daytime and nighttime travel. Drawing insights from research, and the existing coach geometry, four distinct design directions were developed. Emphasis was placed on striking a balance between coach capacity and passenger comfort, recognizing the inherent tension between these two factors in this context. One of these directions was further refined into the final concept. In refining the final concept, the emphasis was on creating a passenger experience characterised by privacy, safety and comfort. Two Virtual Reality tests were conducted among other efforts to achieve this goal.

The final concept features a symmetrical coach with a centrally positioned entrance. The entrance aligns with the platform's height, facilitating easy boarding for passengers
with reduced mobility. The central hall houses a self-service bar for acquiring food and beverages. Adjacent to the central hall are seats on both sides. During the day, passengers can occupy these seats, which are configured in sets of two facing each other. No ticket reservation is necessary for daytime travel, and the coach accommodates 72 passengers during this period. Capacity is thereby 10% lower than in daytime-only trains. At night, the seats transform into beds, offering passengers the option to lie flat.
Privacy screens can be easily placed around the bed, and overhead lockers are available for secure luggage storage. The nighttime capacity is 36 passengers, which is the same capacity as the sleeper accommodation in night trains. Ticket reservation is obligatory for overnight travel. The coach incorporates two toilets and two washrooms. Distinct zones within the coach, such as a quiet zone, a socializing zone, and a women only zone for nighttime travel, contribute to a tailored and comfortable passenger experience.

With the evolution of Autonomous Vehicles for the near future, BMW has designed a new seat for their vehicles, whose aim is to offer the greatest amount of comfort possible. Their main challenge now is to transform this level of comfort even when passengers want to sleep on the road, or while charging their vehicles. When it comes to confined spaces such as seats, obtaining a comfortable sleep has always been a challenge.

Taking into account the difficulty in achieving comfortable sleep in a seat, one of the main goals of BMW is to further enhance this seat within the context of sleeping. Sleeping is becoming one of the most popular activities among those passengers during a journey, and it is expected to grow with the integration of fully autonomous vehicles. Therefore, the first goal of the project is to analyze the seat to ensure maximum comfort when sleeping, and the second goal is to tackle the main area of discomfort with a design proposal.

For this, a thirty-minute sleeping research is conducted with sixteen participants, evaluating two different backrest angles (120º and 140º). The results show a preference of reclined backrest of 140 degrees, and an increase in comfort compared to sleeping in conventional seats. All participants had a good nap with this reclination, with an average amount of sleep of fourteen minutes. Regarding the seat analysis, the most uncomfortable part of the seat is the headrest, due to the lack of support for neck and head, and the lack of height adaptability to different demographics. The second area of discomfort is the leg support and the lack of footrest.

With these results in mind, the second goal is to develop an attachable head support that can be integrated in the BMW seat, for offering more comfort while sleeping in a reclined position. The main requirement considered is to make it adjustable in the area of head, neck, and height of the user.

The proposed design consists of two main components: a head support and a neck support. An integrated mechanism in the foam allows the adjustment of both to the width of the head and neck. In addition, a mechanism allows adjusting the height of the support to the desired position. Different prototypes are developed to assess the viability of the design features and feasibility for its integration in the seat.

A subsequent user test involving ten participants is conducted to validate the comfort and functionality of the design. The participants were asked to sleep in the seat making use of the new support. In order to obtain more objective results, four pressure sensors are integrated in the product to calculate the ideal pressure distribution exerted by the users. The data obtained from the sensors corroborated findings from literature research. Additionally, the support significantly increases the comfort after a thirty-minute nap in comparison to sleeping without support.