The Controller of Site Safety (COSS) is a critical and highly responsible role within the rail industry, paramount to ensuring the safety of personnel working on or near the railway line. For anyone working in the operational environment, the COSS is the definitive authority on site safety arrangements.

What is a COSS?

A COSS is a specially trained and qualified individual who is responsible for implementing the Safe System of Work for a work group on Network Rail infrastructure. They are the person who creates and manages a safe working zone, protecting workers from the dangers of moving trains and railway operations. They hold the "possession" of the work site, ensuring no trains can enter the area where work is being carried out, or they establish safe working distances from live lines. Their primary focus is the safety of everyone under their control.

Key Duties and Responsibilities of a COSS:

A COSS's duties are extensive and demand meticulous attention to detail and unwavering vigilance. These include:

• Planning the Safe System of Work: Before work begins, the COSS plans how the work will be done safely, using official railway rulebooks and procedures. This involves understanding the line speeds, types of trains, and specific site hazards.

• Briefing the Work Group: They clearly explain the planned Safe System of Work to everyone in their group, ensuring every individual understands the risks and the safety measures in place.

• Implementing the Safe System: This involves physically setting up protection on the line, such as placing lookouts, setting up warning systems, or confirming a Line Blockage or Possession.

• Maintaining Site Safety: Throughout the work, the COSS continuously monitors the site, the weather conditions, and the work group's adherence to the safety plan. They are the go-to person for any safety concerns.

• Protecting the Work Group: They are responsible for stopping work and moving the team to a safe place if a train approaches unexpectedly or if safety is compromised.

• Communicating with the Signaller: For certain safe systems (like a Line Blockage or Possession), the COSS is in direct communication with the Network Rail Signaller to ensure train movements are controlled around the work site.

• Handing Back the Line: Once work is complete, the COSS confirms that the track is clear and safe for trains to resume normal operation.

• Emergency Procedures: Being fully proficient in managing emergency situations, including first aid and evacuation procedures.

Where a COSS can work within TES:

The COSS competency is fundamental to many of TES's core operations, making it a highly valued qualification across various departments. A COSS can find themselves working in:

• Permanent Way (P-Way): Directly involved in track maintenance, renewals, and repairs, ensuring safety for the track teams.

• Electrification (OLE / 3rd Rail): Essential for managing safe zones around live overhead line equipment or third rail systems during installation, maintenance, or repair.

• Technical Services: Supporting complex projects where precise safety arrangements are critical.

• Possession Management: While distinct from the direct COSS role, individuals in Possession Management often have COSS experience or work closely with COSS teams to coordinate larger work sites.

• Training & Assessment: Experienced COSS professionals can progress to become trainers or assessors, teaching the next generation of rail workers.