Modelling Urban Transportation Using Tree-Attribute-Matrix Models

Abstract

This paper applies the Tree-Attribute-Matrix (TAM) modelling method to a simplified model of an urban light-rail transportation system. The resulting model is a conceptual model that is beneficial for understanding, management and coordination of the system on a high level, in particular when different (interdisciplinary) stakeholders are involved. The paper briefly explains basic terms and terminology of railway systems as well as of the TAM modelling approach. It displays a simplified rail network and how it is translated into a TAM model. The resulting model contains the key physical and logical components of the system. In particular, the matrix depiction between line routes and the platforms they connect is found suitable for gaining oversight and identifying points of high complexity. In this case, there are five platforms that are serviced more by line routes than the other platforms and can be considered bottlenecks for service operation. The TAM model is considered less well suited when it comes to a complete description of realistic timetables and rail network plans, which require more detail (such as turnouts and track sections) as well as more quantity of data in the model (e. g. the number of trips made per day).The conceptual TAM model discussed could be generalized to include other urban subsystems and their interactions, such as critical infrastructure systems. In that case, such a model would provide a common ground regarding understanding and terminology between different stakeholders, highlight points of strong interactions and allow to discuss the impacts of failures within the system on a high level.

Organizational Complexity as a Contributing Factor to Underperformance

“…The TAM modeling method is based on the observation that the organizational structures of well-formed human-centric systems, i.e., systems designed by humans and for human usage, typically exhibit similar patterns that can be visualized by arranging the system into components (here called aspects) that can be seen as trees, attributes and matrices [34,35,57]. These components can be formally described as three equivalence relations T, A, and M.…”