Our client provides CCTV systems to passenger train manufacturers across the world. Our client was developing its next generation CCTV system and Zircon was contracted to work closely with them to provide the software element of the system.
Zircon was responsible for the design and development of the software and its integration with client provided hardware and subsequent testing. The system was required to be developed in accordance with EN 50128 Safety Integrity Level 1 as Driver Only Operation, where the driver is responsible for ensuring whether it is safe to move off, was a requirement.
The CCTV system consists of a number of components:
- Saloon, Door, Front/Rear Facing and Roof cameras
- Video Recording Unit
- Network Switches
- Drivers Touchscreen Interface
- Off-train playback software
Zircon developed software for all of the above elements.
The software was designed to allow the system to self-configure itself as components are added and removed from the CCTV system network. Video footage is continually recorded onto hot swappable disks until all available space is filled before the oldest recordings are overwritten.
The CCTV system receives alarm messages (passenger or fire) from the train and if an alarm is triggered then the recording of the incident, and a period of time either side, is archived. Video is recorded in a secure format in accordance with Home Office regulations and separate playback software developed to prevent tampering to allow video footage to be used in legal cases.
On arrival at a platform, the drivers in-cab display is activated to show images from the Door cameras. The driver is then able to ensure they are free from obstruction before moving off. If an alarm is raised, then drivers display will switch to the nearest camera to give them a view of the incident.
Zircon’s involvement started with developing and defining the client supplied system requirements into a set of clear and traceable points. These requirements were then used as an input into the System Architecture Design, where the System was split into a set of components. Each of the identified components was then analysed, designed and captured in a Component Design Specification. These specifications could then be used by the Zircon development team to develop the code. In order to ensure the production of maintainable code, and reduce cost at later stages in the products life, Zircon worked to a set of coding standards and gave great care to carry out regular code reviews and static analysis. Component, System/Integration and Acceptance testing was then used to ensure that the developed software conforms with the original requirements and was fit for purpose.
Due to the safety aspects of the system, the software had to be robust and reliable and the integrity of the live and recorded video footage maintained at all times, and as such the software was developed in accordance with EN 50128 SIL 1 procedures and to Zircon’s BSI accredited Quality Management System.
Before final handover to the client the system was tested and reviewed by an independent third party to ensure the system met the EN 50128 SIL1 standard and that the system assurance procedures had been followed correctly.
Zircon successfully delivered the software to our client and has subsequently provided support services to our client as they introduced and modified the system for new clients.