Salthouse Footbridge – Petts Wood, London

Designing a 34 metre footbridge spanning 7 railway lines at the Petts Wood Junction in London

The challenge

Salthouse Footbridge is located just north of Petts Wood Station and provides a public footpath over the South Eastern Main Line. The footbridge is part of a local route between green spaces and provides access to a school.

Inertia Consulting Ltd were chosen to design a new bridge to modern standards to replace the original footbridge which was in poor condition.

Engineering Consultancy

The project began with us undertaking a comprehensive survey and capacity assessment of the existing bridge abutments. Our engineers then designed new, precast concrete abutment cills to modern standards to enable re-decking, as well as a lightweight superstructure for the 34m bridge. All designs were made to the latest Network Rail standards, with our engineers undertaking Form F001, F002 and F003 designs and acting as CRE.

Petts Wood Junction is one of the busiest junctions in the country, which meant the entire project had to completed – including removing the failed bridge and installing the new abutments and bridge deck – within a 52 hour window. This was complicated by the weight of the old bridge exceeding the capacity of the rail cranes used due to access preventing use of road cranes, so our engineers designed temporary works to enable it to be removed in two sections. The new bridge was then lifted into place in one piece due to its lightweight design.

Inertia Consulting managed the entire design process in-house, including carrying out Interdisciplinary Reviews (IDRs). Our team also acted as Contractors’ Responsible Engineer. The new Salthouse Footbridge was successfully installed in 2018 and will provide safe passage over this busy stretch of railway line for decades to come.

The outcome

The footbridge was successfully installed in 2018. Locals can now cross the railway line at Petts Wood Junction on a new bridge. Having been designed to the latest structural and safety standards, the Salthouse Footbridge will offer safe passage over this busy stretch of railway line for decades to come.

The project team
  • Network Rail – the Client
  • Costain-Principal Contractor
  • Briton Fabricators-Steel Fabricator
  • Inertia Consulting – Scheme Designer & Contractors’ Responsible Engineer