In 2020, we were approached by a major provider of maintenance, refurbishment, and upgrade services for diesel locomotives within UK operating fleets.

The brief was to supply moveable, demountable access equipment for safe working on the roof of Class 66 locomotives—specifically to facilitate the removal and replacement of silencer sections.

This required a working platform approximately 4m² in area, positioned at roof level on a locomotive with a distinct angular roof profile.

Cantilevered guardrail frames were quickly discounted due to:
• Poor safety performance of long folding guardrail elements
• Difficult assembly and deployment
• Unacceptable instability risk—especially during relocation
• Lack of secondary access or emergency escape route

Stair access was specified for primary access, with a preference for equipment that could be dismantled quickly for compact storage.

By introducing new components into the Alto HD 1139 range, we developed a structure offering stair access to cab level and the edge of the roof outline. The solution included:
• Linked double-width towers with gated access to the upper level
• Rigid guardrails contoured to match the locomotive’s roof profile
• Drop-down “drawbridge” panels for safe gap-free access to the roof
• Single-width towers providing secondary access without obstructing ground-level gangways
• Fully handrailed stair access for all main routes
• Detailed assembly and dismantling plans compatible with PASMA competence frameworks

Following successful deployment, the client requested additional functionality. A second bridging unit was added at buffer beam level, allowing direct access to the locomotive front and hop-up access to the horn box equipment.