Since my last post, I've built a real stone portal for my trolly line where it enters the underside of Mt. Randolph. I've also used real stone for the hillside that runs along side the trolly line decending from track level of the Mountain Division. The trolly line is entirely elevated on the layout, making for a second level to my Free State Junction Railway which runs above the fictitious town of Patsburg. The east end of the trolly line terminates at a bumper on the inside of the underside of Mt. Randolph. The west side of the trolly line will terminate at Patsburg Westend, a shopping district.
Having the trolly line run inside of Mt. Randolph alludes to the interurban days. i use an Atlas O trolly. ( See accomp. photos )
I used real rocks which I got out of a nearby river bed. I glued the rocks together using Sinbad glue ( great stuff !! ) which I picked up at York. Using Sinbad to glue the rocks together insures there will be no rock slides. 
The top rock over the portal is a long sort of "slab" rock, which fit quite nicely into the space. The portal does not look at all like any "classic" portal, which from my standpoint is pretty cool. As I planned my layout, I did not want to have all of one kind of portal. I want to give visitors the impression that the railroad was constructed over a period of many decades so different kinds of stone, materials, and cuts were employed. At present there are a total of 8 portals on the layout and I use 6 different kinds of portals .... one MTH single portal ( heavily weathered ) for the east portal of Mt. Randolph on the Mountain Division, a Scenic Express wooden portal ( also weathered ) on the west end of Mt. Randolph. For the double track main lines on the bottom deck of my layout I use 3 K line double track portals, an MTH double track portal ... which I had to widen a bit and cut the top higher to accommodate GG1 panagraphs... and a unique looking single portal that I purchased at a local train show.
I hope you enjoy the accompanying photos showing the rock hill, portal, a view of all 3 layout levels, and a Y6 taking the bridge.
