|Continuing. Used a scale (more or less) 3-in. x 6-in. Guard Timber and 2-in. x 6-in. lumber for the foot-walk. I have a little more walk to finish then need to put bolts into the guard timbers .. and finally the railings.|
By accident this morning I found some info on foot-walks on a trestle. From “Proceedings of the American Society of Civil Engineers, Volume 43, Part 2” .. page 2221
“The standard ties are 6 by 8 in. in cross-section, full dimensions, and are 8 ft. long. For the outside tracks, where a footwalk is required, every third tie is 12 ft. long and carries the footwalk”
Ok. Whatever the length of the ties they added 4 ft. Mine extend three foot. It appears from the drawing that that extra foot was used for a kneebrace for the railing posts.
“The outside footwalk, laid on the 12-ft. ties, consists of five pieces of slatting, 2 by 6 in. full dimensions.”
The ‘slatting’ have a gap between them .. say ½-in. giving a total width of about 32-in.
That’s pretty much the width I ended up with. I didn’t extend the ties that extra foot though. Hindsight .. yeah I probably would. Instead I went with something similar to what was used for the.. where looking at it now I realize that at least in part the lack of a kneebrace is simply because the design with posts and railings on three sides doesn’t need that.
I’m not going to go back and re-do the design now. Each post is held with two bolts so it’s not exactly weak .. but .. like a lot of what I do I like to think .. “How would they have done it?” (meaning .. at this point the guys building the trestle go .. “ummmm…” .. and figure a way around it.