I had a difficult design problem.
The main depot area had to be incorporated into the patio area, the only real outdoor area that made sense.
But I live on the side of a mountain, so that meant no easy way to run track from that point.
The bridge/trestle not only gets me to the point where I can run the main line up thru my valley,
but is a usable place to put a pair of reasonable length arrival/departure tracks,
as well as a drill track long enough to assemble a 60 boxcar consist for the Big Boy.
There is not a level area on the entire property large enough to do that...
I am using turboCAD as we speak to design a concrete form for the 2 tunnels where the main/turnaround passes thru the inner yard fence.
Weather permitting I should be able to pour the 1st tunnel tomorrow, then the 2nd several days later
(re-using the form so have to wait 2-3 days before stripping).
After that I am going to build a "mountain" on top of them,
with a combination of tan breeze and granite rip-rap left over from a previous dig on the property.