Well to honest I just used what ever came to hand as the the end result if moulded right should be self supporting when the concrete sets of properly. So I assume that even if the timber rots away it will still stand up. I make this assumption on the grounds that I have spent 40 years in the concrete moulding industry. The main support is at the back, where the concrete does not touch the ground, I put in two steel posts with a cross bar up first and then built forwards from that, so if and when the timber gives way the concrete is supported on its steel legs at the back near the fence. None of this structure is fastened to the fence. I have an arrangement with my neighbour that if I need access to the tunnel I can go in his garden and lift up the fence panels. You may also have noticed that I put up side timbers each side of the track in the tunnel so if I get a derailment or any other type of problem locos and rolling stock will not fall of the track bed. Any help I can offer for the use of Concrete in the garden I am only to pleased to providedunnyrail said:Dear Granddad, in posts 23 and 24 you show some uder mountain structure, all very nicely cut to shape and secured in place. Just out of interest what did you use? Was it Marine Ply or perhaps smaller timber just cut to shapes?
Looking for more ideas as always for the new Dunny Reichesbahn when I sell my House and get a bigger Garden.
JonD