Mark, Just thought of another prototype you might consider adapting for your elevation issue. Getting a railway across the Blue Mountains just outside of Sydney was a challenge because surveyors found every valley terminated in a Cliff, not a pass. The rugged terrain of the Blue Mountains presented a formidable obstacle as they pushed west.
Engineers tackled the major elevation challenge by constructing the zigzag railway, which used a series of switchbacks to navigate the steep gradients. Completed in 1869, this engineering marvel facilitated the expansion of the NSW railway westward, opening up New South Wales to trade and development.
It’s been reopened as a tourist line. If you can convince your other half for a 21 hour flight, you won’t need a car. It can be reached by intercity train👇
Tunnel is about 40 inches.
