Train and Railway Safety Systems

It’s recently been noted by various posters from the Rail Delivery Group that the UK rail network is the safest in Europe. Much of this is through the hard work and diligence of bodies like the Office of Rail Regulation, the Rail Accident Investigation Board, as well as the many Train Operating Companies and Department for Transport. The Rail Safety Standards Board also plays a key role in ensuring our trains and the railway remains safe to use through the development of the Rule Book – and the staff and train crews on the ground who follow the myriad rules and regulations required to ensure your train stays safe no matter what the conditions.

So what tools are available to staff in keeping you safe? Inside the modern train cab (or even not-so-modern cabs) there are now a number of devices used to ensure your safety. In modern trains, even the design of the cab is there to ensure that in an emergency, the train is kept as safe as possible.

  • Power-Brake Controller (PBC) – controls the speed and braking of the train in one control mechanism. Converse to what you may think, to make the train move forward, the PBC is moved backwards. In the event of the driver losing consciousness, this means if they slump forward, the PBC is likely to be pushed forward – applying the brakes rather than increasing the speed of the train. On modern trains, a button must be pressed to allow you to move it, preventing accidental movement. If it fails, the train is taken out of service. On Multiple Unit trains, the Guard can also use the PBC in other, non-driving cabs, to activate the brakes in an emergency.
  • Driver’s Safety Device (DSD) – commonly known as the Dead Man’s Switch, and one of the oldest pieces of safety equipment in use. Now a pedal on the floor of the cab, the driver must apply active pressure to keep it pressed down – or emergency brakes are applied to the train. Note that resting your feet on the pedal will not cause it to press down; rather, the driver must push the pedal down and keep it that way. If it breaks, the train can continue in service – but only with a Competent Person in the cab with the driver (that is, a Guard or Driver, etc. trained in Rules knowledge linked to the DSD) to ensure the driver remains vigilant and focussed on driving, as well as operating the emergency brake if required.
  • Driver’s Vigilance Device (DVD) – linked to the DSD, the DVD comes into action after time of inactivity. If the driver has not moved any controls for a certain amount of time (which, on long runs like Waterloo-Weymouth services, which may call at Clapham Junction and then Basingstoke, is not unthinkable), then an alarm sounds -they must then relieve the pressure on the DSD pedal, and reapply it in a short amount of time. If they fail to do so, then the emergency brakes apply to the train. With modern radio systems (GSM-R), this also now causes an alarm at the nearest signalling centre, so the signaller must contact the driver to establish the status of the train. A faulty DVD is dealt with as per the DSD.
  • Automatic Warning System (AWS) – the AWS is another relatively old system of train protection, having been around in some form since the 1930s! The AWS activates when the train approaches a signal that is displaying anything other than a green “proceed” signal via a beacon on the track between the rails. If a colour other than green is displayed, the AWS sounds an alarm in the cab – which requires the driver to acknowledge by pressing a button within 6 seconds and releasing it. If they do not release (e.g. they have lost consciousness and are leant on the button) then the system will apply the brakes. If this equipment breaks in service, it can be isolated to allow the train to continue – often a competent person will travel with the driver, and the driver must provide a running commentary of the route ahead as they drive to show their acknowledgment of signals ahead – or the train’s speed must be severely limited. Additionally, temporary AWS beacons can be placed on the line to warn drivers of impending speed restrictions or other hazards.
  • Train Protection and Warning System (TPWS) – a more modern version of the AWS – although AWS is still in use. This system is used for preventing collisions between trains by stopping trains that are travelling at unsafe speeds. It does this with two electronic grids set (normally) one second apart at a safe speed – either the speed of the line or a speed so that a train can stop safely in front of a signal. If the train is travelling too fast – crossing between the grids in less than one second, then the brakes are applied. In this event, and with AWS activations, the driver must contact the signaller and wait for a 60 second timeout before he can continue.
  • Wheel Slip Protection (WSP) – analogous to ABS in cars, this helps to prevent a train losing control in slippery conditions by releasing the brakes on affected wheels, before reapplying them as traction is gained again. It is often noticed by hissing from the wheels as air in the brake reservoir is vented, as well as a back-and-forth rocking as brakes are applied and released.
  • Radio System (CSR/GSM-R) – radio systems allow the driver to contact the signaller in the event of any issues, or for the signaller to contact the train. Cab Secure Radio is the current standard, but is being upgraded progressively to GSM-R, which is based on mobile telephone frequencies and offers much more functionality – including specific buttons for emergency usage that stop all trains, as well as priority calls to the signaller. The signal centre can also use the system to broadcast messages and even utilise train PA system to address passengers. In failure of this system, the train will be taken out of service – a reflection of just how important the system is, as well as the zero-tolerance approach of all TOCs towards mobile telephones in the driving cab!
  • Emergency Stop Buttons, Passenger Alarm Units/Passenger Communication Cords, Egress Device – These are various systems, both in cabs and saloon areas, to allow you to contact and communicate with the driver. In older trains, they will just apply brakes or sound alarms in the cab. On more modern trains, they also allow you to talk to the driver and for the driver to talk back.
  • Crumple Zones – modern train design features crumple zones to help negate the force of impact on carriages – this is why modern train designs often have creatively shaped fronts!
  • Anti-climb bumpers – after the Clapham rail crash in 1988, significant issues were found with the structure of the carriages, which led to them telescoping through one another, as well as riding on top of each other. Modern train design features anti-climb bumpers, located at the chassis level of the carriage, which are the ribbed end shapes at the end of the carriage. These lock together in the event of the carriages being forced together, and prevent them from riding up and landing on top of each other.

As you can see, there are a plethora of safety features already mounted on trains of most ages in the UK – and all trains, even steam engines used on the mainline in the UK are required to have the basic safety features fitted. Research is consistently underway to improve safety, from new brake designs, carriage structure and seating improvements, as well making current systems more effective.

On top of this, there is the crews’ knowledge of their routes (to be gone over in a later post) and their stock, as well as their rules training, which allows them to respond proactively and promptly to any emergency thrown their way.

All part of keeping the railway the safest it has ever been.

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About The Rumour Desk

I'm a 29-year-old Content Executive with South Western Railway, and blogging about my work, and my industry.
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