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Alert: Low Clearance of a Locomotive in a Construction Tunnel Boring Machine Gantry

  • Issued: July 30, 2015
  • Content last reviewed: July 2015

Disclaimer: This resource has been prepared to help the workplace parties understand some of their obligations under the Occupational Health and Safety Act (OHSA) and regulations. It is not legal advice. It is not intended to replace the OHSA or the regulations. For further information please see full disclaimer.

Hazard summary

A locomotive operator sustained fatal head injuries when their head became trapped in a gap between two overhead beams of a tunnel gantry while the haulage locomotive was in motion.

During tunnel construction, a locomotive is often used to haul excavated material from the tunnel boring machine (TBM) to a vertical shaft for disposal. There may be limited overhead clearance between the haulage locomotive and the beams of the gantry that is set up behind the TBM to support electrical and mechanical equipment in smaller tunnels – i.e., those that are less than two metres in diameter (see Figure 1, Low Clearance Tunnel Boring Machine Gantry).

Figure 1: Configuration that led to the fatality – Low Clearance TBM Gantry (worker’s head shall not be allowed to protrude beyond the highest point of the adjacent structure on the locomotive)

Figure 1 shows a haulage locomotive pulling a muck cart. The operator's head protrudes above the top of the locomotive's highest point, which is the battery box. This must not occur as it  would allow for shear trap points where gaps between overhead steel beams are not covered.

Locations and sectors

Tunnel construction projects where a haulage locomotive is used.

Applicable regulatory requirements and additional precautions

On a construction project where haulage locomotives are used in tunnel construction, workplace parties must comply with the requirements set out in sections 93 to 99 and 306 to 313 of Ontario Regulation 213/91 (Construction Projects) under the Occupational Health and Safety Act (OHSA).

Regulation 213/91 requires that any tunnel must have enough clear space for the passage of vehicles, such as haulage locomotives, and the movement of workers. The Regulation also requires that a constructor or employer provide a cab or screen to protect a worker who is exposed to an overhead hazard while operating a vehicle.

Additional steps to protect workers pursuant to clause 25(2)(h) of the OHSA may also be required. Constructors and employers should consider other precautions (e.g., additional barriers/guards) to protect workers from other types of hazards (e.g., contact with other moving vehicles) which workers may be exposed to when operating a haulage locomotive in a tunnel. Other types of considerations to protect workers would include:

  • Conducting a hazard assessment regarding the risks and hazards for a worker operating a locomotive in areas with limited clearance.
  • Providing workers with protection by a seat belt, harness or other effective means of restraint during operation of the equipment.
  • Signage to warn workers of low clearance hazards, or automated devices to stop the locomotive in the event of a hazard.

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ISSN 1195-5228

Disclaimer: This web resource has been prepared to assist the workplace parties in understanding some of their obligations under the Occupational Health and Safety Act (OHSA) and the regulations. It is not intended to replace the OHSA or the regulations and reference should always be made to the official version of the legislation.

It is the responsibility of the workplace parties to ensure compliance with the legislation. This web resource does not constitute legal advice. If you require assistance with respect to the interpretation of the legislation and its potential application in specific circumstances, please contact your legal counsel.

While this web resource will also be available to Ministry of Labour inspectors, they will apply and enforce the OHSA and its regulations based on the facts as they may find them in the workplace. This web resource does not affect their enforcement discretion in any way.