created a continuous beam along the length of the viaduct above the top of the masonry piers. Class E: The shallowest valleys at Grove, Draw Wood, and Probus were crossed by simple trestles of three parallel fans with two struts each in a V shape. Brunel's designs allowed any defective timber to be withdrawn and replaced. The first decay usually occurred at the bottom of legs where they were seated in the cast iron chairs, and around bolt holes. The other area with significant decay was generally underneath the decking that carried the track and ballast. After World War I it became difficult to obtain the preferred yellow pine and other timber with shorter life was used instead, although by this time only the viaducts on the Falmouth branch remained in use. Special gangs of men worked together on the viaduct maintenance. To reach timbers below the deck they worked from manila ropes. It was possible to work on the viaduct without closing the viaduct to trains, but a temporary speed restriction was enforced until the replacement was properly in place. The actual movement of the larger timbers was carried out on a Sunday when there were few trains operating. Viaducts from Plymouth to St Germans Stonehouse Pool Milepost 247.25 on original Millbay to Devonport line between Five Fields Lane (now North Road West) and Stuart Road, south of station. () The only double track viaduct on the line, it was a Class A viaduct but with five fans of struts on each of the dwarf piers. It was high and long on 5 dwarf piers. Rebuilt with iron girders on brick piers in 1908. The land below the viaduct was the head of a tidal creek but is now drained and forms a park. In 1876 a new Cornwall Loop between Plymouth North Road station and the Cornwall Railway was opened, built on a viaduct alongside the Stonehouse Pool Viaduct. Millbay station and its connecting lines (on which Stonehouse Pool Viaduct was located) were closed in 1964; the girders have since been removed and a steel work of art has been erected in its place. Keyham Milepost 248.75, north of Devonport. () A Class A viaduct high and long on 6 piers. It was rebuilt using iron girders in 1900 which were again replaced with steel in 1937. Weston Mill Milepost 249.5, north of Devonport, above Weston Mill Creek.