Staging Level with Slide Out
Slide out option to allow access to staging tracks and wiring, and to allow access to the underside of the main level yard for maintenance.
Slide out shelf may be 1/2" ply with 1/2" Homasote or some other, lighter materials, or possibly just straight 3/4" plywood.
Shelf as drawn would be about 14.5 feet (~ 4.5m) long. Clearances would be the same as described on photo 17; ~9 - 9.5 inches to bottom of the main yard above. Roadbed level is 33.5", track level about 3/16" higher.