As I've built and modified layouts, I've come up with some general rules to follow that keep me out of trouble.
These are pretty basic and can be utilized with any model scale you are working with.
These basic rules can be generalized to fit your choice of scales.
I recommend you start by selecting the scale for your model trains and layout (I told you this was basic stuff!).
The next step is to estimate the amount of space you have to fit your layout in.
Take some measurements, make some estimates, and leave room for "error.
" I make some rough sketches to get the ideas out on paper and see how they will work in the space I have.
I do scaled drawings so that I know I am close.
You'll want to determine the smallest dimensions you can have in the layout for grades, turnout angles and curves.
This all depends upon the locomotives and rolling stock you are using.
Short trains can use smaller radii on curves and turnouts, and larger and longer models will require the longer radius curves, up to 30" for HO scale.
Prototype railroads have a maximum grade of 3%, however, if you are willing to "cheat" a little you may be able to go to 4% or even 5%, if you are using powerful locomotives and/or shorter consists.
When a layout has crossovers, you'll have to have from 3 to 4 inches of rise (in HO scale).
Remember to factor in ballast height, load heights, etc.
Minimum Clearances For Your Layout When tracks are running next to each other, you must verify the clearances.
You don't want two trains to bump into each other, causing derailments! The turns are particularly tricky - the simplest method to check it is set up two sections of curve and set your largest locomotives along them, and note how far the ends of the cars project over the track, and how far the middle of the car is over the inside of the track.
How to Draw Your Layout I start my drawings (to scale) by drawing the outside measurements of the space I am working with, including any fixed obstructions (like posts).
Next I sketch major scenery (rivers, roads, towns, farmsteads, etc.
) When replicating a real place, I work from maps, or measurements if I have them from a scouting visit (model railroaders have excuses to travel to some pretty interesting places!) After that I locate the major curves in my layout.
I know which curves are going to have ninety degrees, so I'll draw a circle there using the radius I need.
I place circular arcs at the major curves.
I then connect the circles with straight lines or broad curves to fill in my tracks.
At this point, I'll locate sidings and switching yards.
Try placing these in a variety of locations.
Use your imagination and visualize as much as you can.
This is where using pencil, or a computer CAD program for track layouts comes in handy.
To be thorough, I draw out an elevation plan to check grades and height.
This is important if you have crossovers or changes in elevation, so you can check the track grade.
I start at the "bottom," where the lowest point is, and set this as my "origin.
" I measure up from here.
Make it easy to measure from, both on the drawing, and on the physical layout.
Finally - Building Your Model Train Layout You can make a full size layout drawing and lay out your track right on top of it, or trace through it to your bench top.
Most of us are going to be printing it out on smaller pieces of paper, which we tape together.
Make sure you keep them "to scale" before taping together, by measuring across several of them to ensure accuracy.
Instead of printing it out full size, you can mark out a grid system on your bench.
Draw out an X and Y axis, at 90 degrees to each other, and then you can transfer your major features from the scale drawing to the bench top.
As you build, check by placing track, buildings and other features on the partial layout.
Make any necessary adjustments as you go.
Remember to take frequent breaks to run your trains through your layout, and have some fun!