I have realised in the last few days how little I know about bridges and their design and how much there is to learn! After some fairly rudimentary research I realised I was trying to build what I think is referred to as a "half-through" bridge where the top girder flanges are above rail level and the bottom ones are well below track level to support the beams that in turn support the ballast/track etc. I hadn't previously spotted that the webbing stiffeners on this type of girder would normally just be on the outside. Since realising these things I've had to raise the level of the abutments and this can be seen in the picture. I'm going to use rivet decals on the plating as life is too short for most of the other ways people seem to do rivets! The handrails will be soldered up from brass wire and angle strip. I may decide to re-align the retaining wall nearest in the photograph, when I've finally decided what building will go next to the road in the foreground.