Tomorrow's Railway and Climate Change Adaptation Final Report

4.14 Task 4C Metrics evaluation, consideration of
metrics used in other tasks, and Task 4D Metrics
evaluation, characterisation of the railway as a system
of systems
Tasks 4C and 4D were undertaken and reported as an integrated exercise with Task 3D
and Task 5B. The conclusions from the integrated report are provided in Task 3D.
4.15 Task 4E Metrics evaluation, identification of
dependencies
Task 4E has aimed to understand the dependencies of railway assets on other external
systems, such as road and public transport systems. The operation and maintenance of
various railway sub-systems depend on these. For example, local roads facilitate the
movement of railway personnel, materials and goods to stations, depots and
maintenance sites.
The methods used by existing studies to undertake interdependency analysis were
found to be inappropriate for this study. This is because the nature of the dependencies
of railway subsystems (for example on control centres) on external systems cannot be
captured by macroscopic (economic) indices or geographical proximity. Task 4E first
developed an analysis framework, which considers the channels of flows/ interactions
between railway sub-systems and external systems. These channels included people,
material, machinery/ devices, power/ fuel, communication/ information/ data, and
other flows.
The railway sub-systems considered included tracks, civil engineering infrastructure (e.g.
bridges and tunnels), signalling and control systems, electrical power supply systems and
rolling stock systems. The external systems considered were electrical power supply
systems, water-related systems (such as flood defences, run-offs, sewerage and ground
water), transport systems (such as road networks and public transport systems), fuel
supply systems and natural environments.
A desktop study was carried out using the analysis framework. The task identified key
dependencies and found that further investigations can use the dependency analysis
method developed in this study. Because it would require considerable efforts to
compile a complete list of dependencies, we suggest that further investigations should
focus on key subsystems (e.g. electrical power supply and water systems) in key
geographical areas (e.g. certain sections of railway).
69