KGAL Fluid SUMMER 2026 - Flipbook - Page 6
consulting engineers
Bedford Lock Mitre Gate
In the 2024 Winter issue of ’fluid’, we introduced the challenge at Bedford Lock; replacing ageing timber
components on a historic navigation structure while maintaining its traditional operation and appearance.
View looking downstream at the newly installed Mitre gate and associated parts in the dewatered Lock. KGAL designed stoplogs
downstream of the gate
That work has now reached a major milestone.
On 30 April 2026, the new KGAL-designed mitre gate was successfully opened and is now fully operational,
allowing navigation to resume through Bedford Lock on the River Great Ouse.
Delivered for Jackson Civil Engineering on behalf of the Environment Agency, the project centred on replacing
the downstream mitre gate and associated built-in parts. The new design combines a steel gate structure with
stainless steel heel posts and traditional timber mitre posts, preserving the lock's visual character while
significantly improving durability. Our design also included new stainless steel quoins, pintles, sill, and top
anchor arrangements, replacing the original timber and steel components that had deteriorated over time.
Careful attention was given to retaining the lock's historic operation. The original manually operated penstock
paddles on each gate leaf were replaced, while the existing gearboxes were refurbished and reused to maintain
the structure's traditional look and feel.
One key engineering challenge was operational balance. Unlike the original timber arrangement, the new gate
structure is steel, yet still needed to be manually operated within a constrained space. To achieve this, KGAL
incorporated buoyancy sections within the gate structure and shortened balance beam arms, allowing steel
ballast plates to be introduced and finely adjusted to meet the required operating balance.
The gate and all built-in parts were manufactured by Centregreat Ltd in Wales. To minimise installation risk
and avoid on-site delays, the entire assembly was fully trial-fitted and dry tested in the workshop before being
transported for installation in 2026.
View of the right-hand side Mitre gate leaf in the open position
in a dewatered lock, showing the new Sill, Quoin and
Top Anchor assemblies.
