Roof Gantries and Walkways

Contract Investor:

Network Rail - Kier Construction

Contract Location:

London, UK

Contract Value:


Surface Area:


Gantries, Walkways, Stairs

Ally Structures was an important subcontract in the refurbishment of the Kings Cross Rail station, London. As well as the successful temporary works access we provided. We were also the provider for the roof gantries and associated walkways and stairs.


The station roof consisted of 2 dome shaped rail sheds 30m wide and 250m long. The domes were joined by a central gulley that acted as an access point.


The Brief

Ally Structures was tasked with designing, manufactured and installing several elements of the project. A complex design period was undertaken.


The brief was to replace the existing roof walkways with new aluminium walkways. The existing walkways were to be removed and replaced and additional walkways added.


Access stairs were to be added at either end of domes for access over the roof into the sides and central gulley’s.


The roof cleaning and maintenance works were to be accessed from mobile roof gantries that spanned between the roof walkways.

The Design

The Ally Structures design consisted of new steel support arms which were fixed the roof trusses. Six metre long bespoke Aluminum beams then spanned between theses support arms.


The beams incorporated an unique track extrusion that would be used for the rollers of the mobile gantries. The beams were braced and covered with a GRP mesh floor finish. Handrails were added and the system complete.


Mobile Roof Gantries

Twelve mobile roof gantries were designed and manufactured at the Ally Structures factory in Chester, UK.


The gantries included 3 types to allow for the curve of the dome. The gantries moved on the unique track and trolleys system designed for this application.


A full size mock up of one side of a dome was replicated in the factory prove the design of the mobile gantries. representative of network rail were attended to approve the design.

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