I want to lay 4mm rail across my Brunel timber viaduct. A temporary fix was a length of flexi track with sleepers attached but now I want to make it prototypical with the rails mounted on longitudinal timber baulks as per the attached photograph of Venn's Cross Waterrow Viaduct on the Barnstaple West to Taunton line. Has anyone done this please? Am assuming lengths of rail with chairs attached. obviously being very accurately laid on top of the baulks.