Mobile Scaffolding is a powered or non-powered portable caster or wheel-mounted Scaffolding. It can be constructed of any components: Scaffolding Tube and Scaffolding Coupler fabricated frames or modular elements and must conform to design, construction and loading requirements for those Scaffolding Systems. The Scaffolds must be braced by cross, horizontal or diagonal braces, or the combination thereof, to prevent buckling or collapse.

Caster and wheel stems are pinned or otherwise secured in scaffold legs. While in a stationary position, casters and wheels must be locked with a positive wheel and/or wheel and swivel locks, or equivalent means, to prevent movement. When manual force is used to move the Mobile Scaffold, the force should be applied as close to the base as practicable.

Two access gantries were assembled on electric driven steel frame wheel bogies traveling on rails. Scaffold gantries where decided to be most desirable as they provide the greatest flexibility for modification with expected tunnel profile changes.