Who is Responsible for What? Combining HTA and RACI for Modelling Cooperation in Remote Operation Center of Trains in Future Railway Sector
Authors: Saager Marcel , Kruse Jörn , Naumann Anja 
Published: June 2024

Since 2020, the German national railway company (DB) has been working on the "Digital Rail" project, with aim to create a better environmental balance, higher travel capacities and smoother processes by 2030. The focus here is on the large-scale use of automation. In the future, trains will run autonomously and identify hazards themselves using sensor technology. Autonomous trains with AI will take over tasks from actors, which means that the scope of actor’s tasks will be transformed. Actors, such as train operators will move away from the train to Remote Operation Centers (ROC). This will require new processes for humans and machines and a fundamentally new digital infrastructure, as humans will now act as a fallback level for the autonomous train. This will lead to new organizational and technical structures (monitoring, intervention in autonomy) for control centers. These control centers can be seen as safety-critical systems with multiple actors depending on each other. Therefore, it is important to look at the cooperation between these actors and how they execute tasks. In our case, hierarchical task analysis (HTA) was chosen to identify the tasks of the actors. In order to conduct this HTA, some assumptions were made regarding the scenario and the actors involved. The scenario depicts an autonomous train running on a track section that has an insufficient infrastructure to support autonomous train operation. The actors are organized in a ROC. There is the remote train operator, who has the task of monitoring the autonomous train and intervenes if necessary, and the dispatcher, who handles the disruption at management level. In our context the AI that controls the train is also classified as actor.This information is now being used to create an HTA and to apply the RACI model (Responsible, Accountable, Consulted, and Informed). RACI assigns these responsibility-roles to the individual actors in a so-called responsibility assignment matrix in which all relevant actors are involved.In addition, each responsibility-role gets assigned a quantitative value that reflects the level of responsibility. This makes it possible to identify tasks that have a high concentration of responsibilities by different actors (depending on the sum of the values). The overall model was then validated and adjusted with the help of semi-structured expert interviews. The experts from the rail digitization sector suggested minor adjustments to the model. The response to applying the RACI model to HTA in the rail sector of the future (for stakeholders in the ROC sector) was received positively.This HTA-RACI-ROC model can be used in several ways. On the one hand, the model can be used to detect patterns between new tasks and roles in ROC in order to provide appropriate actions for the organizational structure. On the other hand, it can be used in design methods for control rooms that use HTAs as input. This would require the development of a formalism of the RACI model to the HTA.