Hello.
We’re building our n-scale layout (based on Kato double track Unitrack, with superelevation) and are finding that the common tunnel portals don’t provide adequate clearance for double-stacks, autoracks, etc when you try to enter or exit on a curve. Our trains either hit the top of the portal, or if I shim it up by about 3/16" the cars will clear. BUT, long cars with their overhang will hit on the sides of the portal.
I’ve looked at using HO single portals cut down a bit since they would provide a little more width\clearance, but the size just looks goofy.
We’re freelancing our layout and run everything from steam to bullet trains and everything between, so creative options are welcome.
Along this same theme, we’d like to have part of a city scene that’s built over the double-tracks mainline. Since we’re having trouble with portals, is there something else we can do for where the trains would enter or exit the tunnels under the city?
Thanks.
I ran into the same problem when building my little layout. I purchased two identical tunnel portals. I cut one in half; the other I cut just the top center portion out. I glued the center portion in between the two halves of the first portal. I had to do a little touch-up where the parts came together with some patching plaster. After painting and weathering, the patch job was totally invisible.
On another area of the layout where I have double track running into a tunnel, I performed a similar surgery. After cutting the center section out of one portal, I made a mold and cast several more sections in plaster. I carefully fitted all the sections together, making my own double portal.
All the portals I used were cut stone style portals which made disguising the cuts easier.
In another area of the layout, I have two tracks that come close to each other as they enter a tunnel. The tracks are at slightly different elevations. While there are some portals that have wider spacing portal entrances that can accomodate two tracks that are close to each other, no one makes a portal that can accomodate the different elevations I had. Using foam core board and paper and styrene strips, I built a mold and cast a custom portal to fit my space.
Except for my custom portal, every tunnel entrance had to be elevated at it’s base to accomodate the height of the roadbed and track. Seems like the manufacturers don’t take into account the roadbed height when they design a tunnel portal.
Hope this helps.