Case Study OPO CCTV System

Background
TfL approached Teletest in 2013 to conduct a feasibility study on one of it's London Underground lines.

This was to study the existing analogue PtF (platform to train) CCTV system, first installed when the line was commissioned, with a replacement system, that wasn't prone to component and manufacture obsolescence.

Historically, there are many different types of PtF CCTV systems on the London Underground network, also known as OPO systems, for Opne Person Operation, and so Teletest needed to consider cross-line compatibility in their study.


OPO CCTV System
These systems consist of 2 - 8 CCTV cameras on each platform, which look down the entire length of the train, the video images of which are combined into one or two video signals.

These signals are then transmitted to the train, and displayed on one or two screen in the cab when the train is either stationary, or when it moves out of the platform.

The driver watches these screens to ensure it is safe to close the train doors and then to pull away. Should someone get trapped in a door or fall under a train, the driver sees this and is able to stop the train.


Study
The first part of the project took place 2013-2014 and was to evaluate the existing analogue equipment in-lab and to determine its features and performance.

The second part of the project was to develop prototypes and to conduct on-site tests in 2014-2015 at a station during engineering hours over three nights. This involved installing the prototypes in the CER (Communication Equipment Room) and testing the heritage analogue signals, with empty platforms, trains present, and on moving trains. Special attention was paid to identifying possible platform crosstalk and interference from trains.
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Conducting on-site tests
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Signal analysis on-site
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Driver watching the PtT CCTV images in-cab
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Conducting in-lab tests
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Signal analysis in-lab
Finally Teletest put together a Feasibility Study for a replacement system for platforms and trains.

The system proposal also had to conform to:
  • Real-time images
  • Instantaneous equipment start-up
  • No active trackside equipment – transmitters located in CERs
  • Approved to all relevant train-borne and trackside standards

Next Step
This project is ongoing. For further information, contact Nick Rose, Managing Director on 01243 696100 or nr@teletest.tv