I am doing a 4x8 layout with three spurs and a frieght yard and around one eighteen inch radius curve I have the track sloping at a 2.5% grade. I wan't a tunnel over this area but My two spurs will get in the way on one area so I will have to shorten my tunnel quite exstensivly. My main question here is: If I have a fairly short tunnel will it still be realistic?? If the engine is exiting the tunnel and the caboose hasn't even entered the tunnel will this still be realistice. Im looking at a tunnel about 2.5 to 3 feet long.
Thanks everyone in advance!!!
Yes. On a 4x8 you need some artistic license. What will sell the tunnel will be the mountian it goes through. I have a tunnel about six incehs long that looks like it needs to be there.
Good luck.
We just hiked through some abandoned Colorado and Midland tunnels a couple of months back. Some of the tunnels were only a couple of hundred feet long.
There are plenty of prototypes for short tunnels:
On the joint UP - BNSF line over Tehachapi Pass (the famous 'Loop' route) there are two short tunnels only a couple of hundred feet apart. Neither is more than a few hundred feet long. For all but the shortest trains, the engines are clear of the second tunnel before FRED disappears into the first.
On the former NYC main line on the east shore of the Hudson opposite Bear Mountain there were (and almost certainly still are) several short tunnels. They pass through rock ridges too tall to simply cut. Building around the ridges was not an option - the adjacent river is hundreds of feet deep.
In more than a few places rail lines in cuts have been roofed over to make some of the world's highest priced real estate available for development. Having a covered cut between two streets with an office building, hotel or hospital on top would not be unreasonable.
There is a classic "Lionel tinplate" tunnel in line with the runway at Yokota Air Base in Japan. The JNR line is in a shallow cut. About 100 meters of it have been roofed over with concrete, then earth-bermed - a long, narrow artificial hill in the middle of otherwise almost level land.
As long as there's a logical geographic, economic or political reason for it, a short tunnel makes sense.
Chuck (who models a couple of prototypes that had numerous tunnels of assorted lengths, and lives where the Raptors live)
Why would biding a tunnel on a curve cause derailments? If enough clearance exists the train doesn't know it is in a tunnel.
I have a 3 foot tunnel on one of my curves and have never had a derailment in the tunnel.
what happens is that a tunnel portal positioned in a curve is not wide enough for trains to go thru using commercially built tunnel portals...the train cars swing out on curves and hit the sides of the tunnel portal rather than going thru it...that's why i scratch build my tunnels making them wider than the commercially built kind..it's a lot of work building the jig, pouring the plaster, the sanding, and a lot of cutting with a hobby knife, but the train never hits the side of the tunnel like they otherwise would with commercially built tunnel portals ... here is a scratch built tunnel i'm putting in now...it has plenty of room in the curve for the train to pass thru without hitting the sides of the portal
chuck
I also build my own portals. They are too expensive to buy already built. It is not that much of an effort.
I use balsa wood to create the forms on a flat surface. I use anywhere fro 1/2 inch to 3/8inch wood strips. I simply pin the wood forms to the surface, pour a rather soupy plaster mix into them and use a metal or plastic straight-edge to level it and let it dry. Do not use a piece of balsa as a straight edge as it will absorb the moisture and not give very smooth results.
I made four portals using this method for about $5.00 worth of material vs. $25.00 to $30.00 for four commercial portals. And I have no problems with width, as they are custom made for my needs.
I sprayed with concrete paint the same as I would have with the ready made portals.
cwclark wrote: what happens is that a tunnel portal positioned in a curve is not wide enough for trains to go thru using commercially built tunnel portals... chuck
what happens is that a tunnel portal positioned in a curve is not wide enough for trains to go thru using commercially built tunnel portals... chuck
Thanks for all your help but how can i tell if my rolling stock will scrape the sides of my tunnel
raptor55
raptor55 wrote: Thanks for all your help but how can i tell if my rolling stock will scrape the sides of my tunnel raptor55
Measure from the center of the track to the overhang. Then add some amount such as 1/2 inc or 1 inch and create a tunnel that does not come within this measurement at any point anywhere in the tunnel.
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
raptor55 wrote:Thanks for all your help but how can i tell if my rolling stock will scrape the sides of my tunnel raptor55