Hi figure8
An Aster 4-6-2 and a train of 16 Basset Lowke scale model (for thier time) G1 tinplate coaches.
Adds up to a fair bit of weight traveling at express speed.
the rabbit didn’t stand a chance no where to run too.
the train did not suffer any damage.and the rabbit did not suffer but the locomotive got its frame bent.
regards John
I used three metal mail boxes mounted on a treated board and covered them with plastic. The size is perfect and so is the shape. I bought plastic tunnel portals which fit the openings perfectly, confirming the dimensions and shape of the mailboxes. I cut off the rear ends of the mail boxes and used duct tape to cover the small gap between each. I nailed each box to the board below for stability. Looks great, works great.
Everything i read says to make tunnel bigger than you really need in height & width, that way you can accomodate some new type of car that comes out 10 years from now, and easier to manipulate derailed cars to get them out. I’d go with a minimum height of 12 inches and width of 8 inches. You just make your portals the size you want people to see.
Much wise advise has been given here on length. that is unless you have some way to put manholes into it and figure out a way to hide them in the scenery.
Keeping wildlife out? Try the 4 inch thich upholstery foam cut about 1/2 to 3/4 inch bigger on all sides, with a chunk of plywood on the back and a knotted string thru plywood, foam, etc. and sticking out to use to pull with. When not running insert plug; and just pull out to run. Had a friend used that to keep birds from nesting in airplane engine cowling. Worked very well.
We used treated wood painted with waterpoofing paint then made the tunnel portal with belgin stone. Our tunnel is curved and we almost used cement blocks, but chose the wood since we had the wood on hand. Flue liners would not have worked well for us because of the curve.
mikadousrp
Don’t forget about one of the simple, cheap and easy ready made shapes for a tunnel out there. The standard #2 rural mailbox.