This case explains how survey data, 3D track data and 3D signals were used to provide a comprehensive data set for signal sighting.
Years of study and analysis of hardware and logic have delivered very reliable signalling equipment. More recent events have highlighted the need to focus on signal location, sighting distances and the way in which signals are interpreted by drivers. This is challenging, as traditional techniques for choosing the positions of signals have become harder to use.
Safety regulations make it difficult for staff to gain access to the track, and increasing traffic means operators wish to minimise disruption. Route learning is difficult because a new layout cannot be driven until it is completed, and even then it may not be possible for a driver to pass along every possible route. The rail industry has thus had to devise new ways of establishing signal sighting, and communicate final designs to train drivers. An approach which has been used on Thameslink Programme uses a 3D computer model of the railway, which can be used to place signals by parametric design rules and then perform objective assessment of sighting, aiding subjective assessment within the real environment.
The role of signal sighting for Thameslink Programme
Thameslink Programme was developed to deliver a major expansion of the cross-London Thameslink Service. It involved the provision of longer, more frequent trains, serving a more extensive network to deliver a substantial increase in passenger capacity through the centre of London. A 16 day blockade was identified from Saturday 20 December 2014 to Monday 5 January 2015 for the LL09 staged works at London Bridge station. Stage LL09 covered:
- The removal of platform 8 & 9
- Remodelling of the station throat
- Temporary track slews
- Construction of crossover
- Installing of much of the final signalling infrastructure, including new lightweight straight post signal.
Using survey data, 3D track data and 3D signals provide a comprehensive data set for signal sighting. This seamless solution allows real-time positioning and movement of signal objects and signs, additionally allowing clash detection modelling. Virtual Modelling is an important component part of the construction phase of many schemes, allowing the model to be used throughout the entire life cycle of projects, from design through to Signal Sighting and on into Driver Training and Simulation.