Callender-Hamilton Bridges
From Graces Guide
The Callender-Hamilton bridge is a modular portable pre-fabricated Warren truss bridge, designed for both temporary and permanent applications. Assembly takes much longer than for the Bailey Bridge as it uses individual lengths of steel sections connected by numerous bolts, rather than pin-jointed panels.
The system was designed by the New Zealand engineer, A. M. Hamilton, and patented by him in 1935. The system is currently fabricated by Painter Brothers, Hereford, operating within the Balfour Beatty Power Networks Division.
The above information is condensed from the Wikipedia entry.