Others, like these in Ponderosa Mountain were merely blasted out of rock. The upper portal, serving the Ponderosa Lumber Company trackage, is a single track bore while the lower one is a double track opening on the Cimarron & Tall Timbers RR main line. A D&RGW C-21 is seen exiting the double track tunnel on the outer track at Ponderosa Siding.

Both the main and branch line tracks of these tunnels that pass thru Ponderosa Mountain await ballast, but the rails within the tunnel portions were ballasted prior to the tunnels being completed. Both are lined with plaster castings supported by untempered Masonite.

This trio of portals was built as one element. The two portals on the left were built first and the single unit on the right was attached later. The basic frame is 3/4" plywood, covered with weathered strip wood. The portals were set in place and plaster scenery built up to touch them. There will be a lift out section to cover these portals, providing access to the tracks below.

Engine 487 exits Cimarron Mountain through a Woodland Scenics cut stone portal. The right side of the arch had to be "notched" to clear the overhang of the cab roof on the larger K-37 engines used to assist trains up the 2.5% grade.