Introduction of Colour Monitors for Level Crossing Operation
Network Rail
Background
The UK rail network includes level crossings which require to be checked remotely using CCTV systems prior to letting trains pass over them. The original systems are becoming life-expired and there are substantial costs involved in a one-to-one replacement of the original black and white monitors
Flat screen colour monitors present a modern, cheaper alternative though safety-related factors need to be checked before this alternative solution can be introduced.
Project
We were commissioned by Network Rail to conduct an applied research study into the human factors of the CCTV operation. The objective of the study was to determine whether there were any operational, and safety related reasons, why a colour flat screen could not replace a black and white CRT monitor.
Implementation
Safety concerns vetoed the testing between the options is a signal box so it was decided to obtain some real ‘footage' from actual level crossings at different times of the day. This involved introducing an extra colour camera at the selected crossing approximating the position of the permanently fixed cameras.
A series of targets were placed on the level crossing to simulate targets which signallers would need to identify in order to judge that the crossing was not clear and the train needed to be halted. These included a wheelchair, a buggy, a small child, etc. Video records were made for different times of the day and for different targets - systematically varying the targets and times of the day to ensure that all conditions were covered.
Following appropriate editing of the raw material signallers, working under laboratory conditions, were asked to carry out their usual judgements of ‘crossing clear' whilst the time of day, targets and screens were varied.
Outcome
The trials concluded that there was no decrement in performance in checking level crossings when cathode ray tube based black and white monitors were replaced with flat colour screens.
For More information
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