OK, I've provided some initial tips for those considering jumping aboard the hobby that is model railroading.
While I'm sure there is plenty more to cover, there is something I feel the need to share.
When designing a model railroad, one of the things we must consider is that simply watching a train go around a track is not necessarily realistic.
Sure, you can set up a simple oval, but how often do you see a train go in a circle in real life?
To fix this problem, model railroaders employ a number of tricks. We use backtrops to cut a layout in half. That works fine if your layout sits in the middle of a room with access to both sides for operation and viewing purposes.
We also use mountains through which the trains must pass, giving the illusion that they are leaving or entering scenes on our layouts. This technique is especially helpful for those of us who have constructed our layouts along the walls of a given room.
I have employed mountains at either end of my layout. They are just big enough for my trains to enter completely before reappearing.
This technique is relatively simple, but there is something important to consider.
While it is pretty easy to lay the track so that there will be little chance of derailment inside the tunnel, nothing is impossible.
If you have ever constructed a layout that included a mountain through which trains must pass, you just might have had the unpleasant and frustrating experience of a derailment therein. There's nothing fun about having to reach through one of the tunnel portals to try to retrieve a missing train car. There's even less fun about pulling up an entire mountain to do the same thing.
With that in mind, and yes I am speaking from experience, I was working on my second of 2 major mountains/tunnels over the weekend.
I am normally a big fan of plaster cloth for landscape construction, but a while back I purchased a grass mat by Woodland Scenics.
The mat comes in rolls, is easily cut to the size you want and can be shaped by heating it with a heat gun and simply holding it in the position you want it until it cools down. Once cool, it will retain its shape.
I used this mat in about the center of the mountain, attaching it to the top of the foamboard I used to form the roof of tunnel and allowing it to drape down to the base of the layout. I heated it, molded it into shape and placed some molded rocks at the ends. I then glued rocks to the layout base being careful to leave the edges of the rocks without glue to allow the grass mat to slip underneath. This conceals the edge of the mat where it meets the layout and allows me to easily peel up the mat to gain access to the mountain's interior should I have to retrieve rolling stock.
Check back in a day or two for a couple pictures that will show what I did.