Monday, October 28, 2019

Safety Message: Passengers caught in rolling stock doors - Risks, causes and controls

A number of incidents have occurred, both in Australia and overseas, whereby passengers have been caught in train doors and in some cases been dragged by the departing train. In recent months ONRSR has undertaken a review of this risk in Australia and is sharing its findings in relation to risk causes and controls with rail transport operators.

Risk description

Caught in rolling stock doors incidents (CIDs) involve a person’s body, clothing or baggage being caught in a train door. Only a small proportion of CIDs become the higher risk Trapped-and-Dragged (T&D) incidents where the passenger is caught in the door and then dragged along the platform. T&D incidents in Australia and overseas have resulted in injury or death, and in some cases, T&D incidents have led to passengers falling between the platform and train, further increasing the risk of injury or death.

Risk causes

Why do people get caught in rolling stock doors?

People (and/or their clothing or belongings such as bags) can be caught during the closing of automatic doors under the following scenarios:

• The person fails to identify the door is closing or is about to close;
• The person identifies the door is closing but continues to attempt to board or exit the rolling stock anyway.
• Persons with reduced mobility (PRMs) who may identify that the doors are closing but are:
• unable to move out of the way in time without assistance
• unable to free themselves from being caught in the doors.

Why do people attempt to board when the doors are closing?

A common causal factor identified in an analysis of both incident data and incident reports was that the passenger was rushing to catch a train that was about to depart. Passengers mistakenly believe that:

• If an object is caught between the doors the doors will always re-open (like the doors on a lift); and
• If an object is caught between the doors the train cannot move.

This has led to passengers deliberately inserting their hand, arm or leg between the closing doors in the expectation they can delay the train’s departure.

Depending on their design and operation, the train doors may not detect an object caught meaning that:

• the doors do not reopen or unlock to allow the person to remove themselves from the doors
• the train is still able to depart the platform.

Passenger behaviour can be influenced by:

• Public education campaigns;
• Audible and visual door closing indications;
• Overcrowding on platforms and trains during peak hour frequency of service – Passengers are more likely to run and attempt to board a train while the doors are closing if the wait time until the next train is significant.

What causes CIDs to become Trapped-and-Dragged incidents?

A CID can escalate to become a higher risk T&D incident when the rolling stock moves while a passenger is caught in the doors. T&D incidents may result in the following:

• The person being dragged along the platform;
• The person being dragged into the space between the platform and train;
• The person being dragged until colliding with an object at the end of the platform
• The person being dragged beyond the end of the platform.

T&D incidents are of a much lower likelihood due to many layers of controls that include:

• Engineering controls, such as obstruction detection (the doors automatically detecting that there is an object caught in the doors and automatically pausing or stopping the door closing sequence) and traction interlocks (an interlock that does not allow the train to move unless the doors are fully closed);
• Administrative controls, such as observations by drivers or guards;
• Encouraging safe behaviour around doors.

Other causal factors that can contribute

The ability of the driver (and other railway staff) to observe the train and platform interface and ensure there are no passengers caught in doors, contributes to the prevention of T&D incidents.

On most railway systems the command to close the doors is issued by the train driver or guard. Therefore, railway staff incorrectly identifying that doorways are clear is another cause of CIDs.

Factors that influence train crews’ ability to detect passengers caught in doors include:

• Platform design – straight platforms provide better viewing;
• Overcrowding on platforms during peak times;
• Length of train and number of doors;
• Viewing aids such as CCTV cameras or rear-view mirrors;
• Drivers misunderstanding the door-closed indication for several types of CID scenarios.

Risk Controls

The following is a list of controls that are available and have been used in other railways both in Australia and overseas. For ease of description, the controls are categorised into the hierarchy of controls:

• Elimination;
• Substitution;
• Engineering;
• Administrative
• Personal Protective Equipment (PPE).

As noted earlier, this document does not recommend or suggest what controls are reasonably practicable to introduce or not, as this is dependent on operational context. Nor is the list exhaustive, as other controls may be or may become available. Instead, this list includes available controls that operators are expected to consider.

Elimination

Full height Platform Screen Doors

DESCRIPTION: Provides a physical barrier between the train and platform. Platform screen doors are also synchronised with the train doors and will prevent the train from moving when blocked. Full height platform screen doors provide other benefits for underground stations. They separate tunnel and platform ventilation systems thereby creating a smoke and fire barrier for passengers on the platform if there is a fire in the tunnel.

BENEFITS: Provides protection from the risk of a fall along the whole platform length. Eliminating access to the train/platform interface prevents some forms of accident and deliberate misuse that can result in falls. Provides protection against incidents caused by platform overcrowding.

Substitution

There are no practical alternatives to powered doors for allowing passengers to board rolling stock. Unpowered manually operated doors may be suitable for some Tourist and Heritage operations but are not practical for mass transit type operations with multiple station stops and short dwell times.

Engineering

The engineering controls railways have employed can be categorised into the following:

• Door-related controls; and
• Traction interlock related controls

Door-related controls

There are two (2) door-related controls that are commonly used on rolling stock:

• Obstacle detection systems; and
• Obstacle removal systems.

Obstacle detection systems	DESCRIPTION: Doors with obstacle detection systems (ODS) are able to detect the presence of an object stuck in the doors and automatically reopen when the obstruction is detected. The sensitivity of the ODS is dependent on its design e.g. some rolling stock is able to detect smaller obstacles of 5mm wide; most rolling stock in Australia complies with the minimum requirements of EN14752 i.e. 30mm. ODS are able to detect an object through methods such as: A sensitive edge; Monitoring the electric current of the motors used to close doors (the effort required to close the doors); Monitoring of closing time; or A combination of methods. ODS are often linked to traction interlock systems (see traction interlock controls below) which prevent the train from moving when an obstruction is detected.	BENEFITS: Automatically detects objects caught in the doors (does not rely on the driver).
		RESIDUAL RISKS: Smaller objects (such as fingers, clothing or bag straps), may not be detected.
Obstacle removal systems	DESCRIPTION: Obstacle removal systems complement obstacle detection systems. If the obstacle detection system is unable to detect an object caught in the doors, obstacle removal systems allow the trapped objects (such as fingers, hands, bags, feet) to be pulled free. Obstacle removal systems are designed to allow thin trapped objects to be withdrawn with a minimum of force. Obstacle removal systems operate independently from obstacle detection systems even though they are sometimes implemented through the same hardware components (such as the door seal).	BENEFITS: Obstacle detection systems have limitations and may not reliably detect smaller objects. Obstacle removal systems, enabling the removal of a caught objects are an additional control.
		RESIDUAL RISKS: Objects such as bag straps with buckles or zippers on coats and shopping bags may not be able to be removed.

Traction interlock related controls

Traction interlock controls prevent the train moving if a person or object is caught in the doors. The two (2) types of controls are:

• Door closed and locked interlock (detects that the doors are in the closed position and the locking mechanism has activated); and
• Anti-drag detection interlock (detects any “pulling forces” that are being applied to the doors once they have been closed and locked).

Door closed and locked interlock	DESCRIPTION: The door closed and locked interlock (also called a safety loop, door loop or green loop) prevents traction power from being applied until all doors are detected as ‘Closed’ and/or ‘Locked’. Thus, if a door is obstructed, the train will be prevented from moving.	BENEFITS: Control provides a defence against a CID escalating to become a T&D incident when the driver fails to identify that a passenger is caught in the doors.
		RESIDUAL RISKS: Smaller objects (such as fingers, clothing or bag straps), may not be detected.
Anti-drag interlock	DESCRIPTION: The anti-drag interlock detects the presence of a dragging force being applied to the door seals when the door is closed. This interlock is complementary to the obstacle detection and removal systems. If an object is not detected, and the person is unable to remove themselves or their belongings from the doors, the anti-drag systems will detect that an object is being either pulled by the person or dragged by the doors as the train begins to move. Anti-drag interlock systems are linked to traction interlock systems and prevent the train from moving when a dragging force is detected.	BENEFITS: Provides protection against passenger clothing and bag straps becoming caught and then dragged by the train. With the limitations of obstacle detection systems to detect smaller objects, anti-drag interlock provides and additional control.
		RESIDUAL RISKS: A person may be injured by the initial dragging.

Passenger emergency stops and intercoms

There are two (2) types of emergency buttons or door release controls that are available for nearby passengers to use if they see someone caught in the doors and the train beginning to move:

• Rolling stock emergency stop/intercom; and
• Platform based emergency stops.

Rolling stock emergency stop/ intercom	DESCRIPTION: The primary purpose of the emergency stop or intercom is for passengers inside the train to either stop the train or alert the driver to a dangerous situation. Passengers observing a CID or T&D incident may operate the emergency stop or intercom.	BENEFITS: Provides a means for passengers to take action should a person be caught in the doors.
		RESIDUAL RISKS: Reliant on passenger intervention which is subject to delays or human error.
Platform based emergency stop	DESCRIPTION: Platform based emergency stop buttons allow platform staff or other passengers on the platform to stop a train from moving when they identify an emergency situation such as a person falling between the train and platform gap, a person caught in doors, or a person trapped and dragged.	BENEFITS: Like the train-based emergency door release, platform based emergency stops give people on the platform the ability take action to prevent an accident or reduce its consequences.
		RESIDUAL RISKS: Reliant on passenger intervention which is subject to delays or human error. Only practical on networks that use Automatic Train Control Systems where train movement commands are issued from a central signalling/control system.

Administrative

Administrative controls can be categorised into the following:

• Driver viewing aids
  • Platform monitors;
  • Platform mirrors;
  • Rolling stock mirrors; Rolling stock in-cab monitors.
• In-cab ‘Door open’ warnings
  • Visual warnings; and
  • Audible warnings.
• Controls promoting safe passenger behaviour
  • Public education campaigns and warnings;
  • Staff presence on station and platforms;
  • Free or reduced fares outside of peak times;
  • Not fully opening doors when obstacle detected
  • Wide, open, clear platforms.
• Passenger warnings.
  • Passenger announcements;
  • Warning tones;
  • Flashing lights;
  • Stickers and signs.

PPE

PPE is not considered a practical form of control for this risk.

If you wish to discuss any of this information further, contact your local ONRSR office or email.