Depot Personnel Protection System

A Depot Personnel Protection System, commonly referred to as Depot Protection System or DPS, is a system designed to protect staff and equipment by ensuring the safe and controlled movement of rail vehicles into and out of train maintenance depot, a process sometimes known as shunting. This allows train maintenance operations to be conducted without endangering the safety of staff, and damaging other maintenance equipment in the depot.

The most important asset in the depot are the people working there, therefore the depot protection system needs to deliver the highest level of personnel security.

A depot protection system consists of these basic elements:

Traditionally protection to a personnel working in the depot was provided using padlocks. Staff would fit these padlocks onto the signal control panel before starting work. With the padlocks in place, it would not be possible to physically access the control panel to set the driver signal to proceed or lower the physical protection.

Unfortunately although widely installed these simple padlock systems do have some draw backs. Padlocks often had to be destroyed when staff forgot to remove them at the end of the working period, in which case they would have to be cut off (though this can be resolved by using a system of padlocks incorporating a master key, to which the supervisor has access). It is also a slow procedural system with poor traceability in the event of an incident. This led to the development of more advanced electronic systems that overcame these weaknesses.

More technically advanced depot protection systems consist of a number of microprocessor-based control panels installed in a distributed communication network, operating using electronic identification keys or tokens, in place of padlocks. Each user is issued with a personal datakey, a portable memory device which stores the user's login details and operational level electronically. Before starting work, the user logs into the system at the nearest control panel to "apply personal protection" to themselves while they are working in the depot. Once a user is logged into the system, the DPS will inhibit removal of train movement protection and clearing of driver signals, therefore preventing a shunter/team leader to authorise a train movement, until all users have logged out of the system.

This system can reduce some of the 'walk time' associated with traditional systems (staff can log on at any such control panel, rather than having to walk to one designated location to apply their personal padlock) but conversely, the ability to log on remotely from the work site does give rise to the opportunity of staff logging on to the wrong work site (e.g. the wrong road in the maintenance shed).

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Wikipedia