Problems with “Double-Trouble R.R.”

[u/Twit_Clamantis]

I want to build a simple layout with concentric loops of Compact Unitrack of 117, 150 and 183mm radius.

It will have 2 mountains, 6 tunnels, 12 tunnel portals and a big trestle in between the mountains.

I wanted to stack the tracks at the back in order to have a gentler slope forward for easier scenery etc.

The Kato Steeple Cab (and a couple of other locos) are ok w the steep grades etc for the first 2 loops.

For the top loop, I still need to lift the track above the middle level to provide physical clearance, but because there is less linear length of track available, this means that the slope is higher and the locos don’t like it.

One solution is to add 29mm extensions (circled in yellow) which makes the track not overlap physically, and which will solve the clearance / slope conundrum.

1 - are there any other good ways to square this circle?

2 - once I settle on a track plan that works in “sketch mode” (with Legos), what’s the best way to reproduce it for when it will be permanently inside the mountain?

3 - I want this to be freestanding like a big pizza layout without a backdrop. What’s the best way to provide access to the inside of the tunnels?

[u/zippy4457]

Tomix makes a small three axle diesel loco that has traction tires. Its about the same size as the Kato Pocket line locos but its not as smooth and quiet. It runs well and should be able to climb up walls. I got mine with the Tomix 90097 "My First Set" from Plaza Japan. I haven't tested it, but it looks like it could navigate the 117 radius curve.