As I built the terrain shell for Noisy Creek Trestle (https://espeecascades.blogspot.com/2018/06/noisy-creek-trestle-and-tunnel-9-terrain.html) I realized I needed to retain a pair of footpads straddling the trestle area for access to the far back corner. The need for those footpads was dramatically shown by one of the photos in that prior blog post, showing me up on the layout slathering Sculptamold onto the terrain shell. Those footpads needed removable terrain hatches.
I began the hatch terrain project by creating a duplicate set of baseplates to serve as footpads when the hatches are removed. I then covered the scenery hatch base plates with slabs of Styrofoam to serve as bases for further Styrofoam construction. Back profile panels were erected to match up to the existing terrain around Tunnel 9 and the RR-West portal and shed system of Tunnel 10. Side profile panels were added and a front profile plate for the Tunnel 9 hatch was created. The scenery at the base of the Tunnel 10 hatch forms the creek and is at the same height as the base plate.
Tunnel 9 access hatch base plate. At this point, the base plate completely fills the space between the fixed scenery and roadbed in front and the wall behind.
Terrain profile panels in place for both access hatches. Tunnel 9 is on the left. Tunnel 10's RR-West rock shed is on the right.
With the edge profiles defined, I filled in the remaining terrain slopes with slabs of Styrofoam. Some of the slabs were built up with two or three sections of my standard one-inch foam material to provide more depth for carving. I then used spray foam to fill cracks and gaps in the shell. Once all of this set, I shaped the terrain using knives and my Surform ™scraper.
Terrain shells for Tunnel 9 and 10 access hatches with spray foam applied.
Moving toward finishing the terrain shells, I needed to test the hatch removal. Tunnel 10's hatch removed fairly easily, but the Tunnel 9 hatch proved very difficult to remove. After much banging and exertion on my part, I found the front corner of the Tunnel 9 hatch extended a bit too much. It both caught the fixed terrain profile in front of it and caught the roadbed at Wicopee when trying to lift it straight up. Trimming work with my oscillating saw (a new tool acquisition this year) freed the hatch and allowed me to remove it. I trimmed it further with my circular saw. The hatch base plate does not need to fit snuggly into the hole. Only the terrain should be "snug."
Tunnel 9 hatch with front left corner trimmed using the oscillating saw. This will remain a tight fit, but the hatch is now removable.
The final step in this project--for now--was to apply the Sculptamold covering to the Sytrofoam shell. I used wax paper at the edges of the shells to retain an edge separate from the fixed scenery. With these two terrain hatches built up, the terrain around Noisy Creek Trestle is a bit more complete.
SP X9322W serving as a BRLAT (Brooklyn <Portland> to Los Angeles Trailers) crosses Noisy Creek Trestle with the flanking terrain hatch panels in place.