2010-06-25

Designing your first or second model railway

This document is intended to help you design a good looking, well operating, layout, using the same resources (time, space and money) that would often result in a "toy like" layout. If you're planning on filling a basement, you may find something of use here, but if you are, you're probably either very experienced or have better qualified help than I can ever be.


Even if you are planning a layout in the range I'm thinking of, you don't have to follow my advice at all, but if you're a beginner, I strongly encourage you to be certain why you aren't following them and something else is better for you. (If you should think I'm wrong, please tell me about it.)




Which type of layout?


There are a number of design considerations that depends on your preferences, which sometimes are mutually exclusive, among them:

realistic scenery --------- lots of tracks
mainline running ---------- switching
countryside --------------- cityscape
prototypical operation ---- just running trains
If you know exactly what sort of layout you want, you're probably not a beginner, or you've had plenty of opportunity operating other layouts so you know from experience what you like and don't like on a layout. But think about it a lot before you actually start to build the layout.
I'm supposing you're a beginner, and will thus recommend that you choose a little of everything, and thus get a "general purpose" layout. Well, there's one exception and that's long trains and large locos which won't fit on a first layout. At least not on a small general purpose layout.


Main categories


Strengths and weaknesses of different types main line arrangements.

Four main types of layouts

The first example is a "point to point" layout.

Pro: This is exactly how real railways look.

Con: Unless you have a long narrow space, this will either give you a very short mainline run or an extremely crowded plan, perhaps with steep grades. Both terminals have to be approximately the same size, as  they have to receive all traffic the other generates. No continous running.

Recommended if you have a suitable space and know this type of layout if perfect for you, or if you have very little space so a pure "switching" layout is what you have to build.

The second is a "out and back" layout.

Pro: Gives an opportunity to model one large terminal with extensive operations, or a smaller one with space for realistic scenery, as no other track has to crowd close to the terminal.

Con: Takes up relatively much space for relatively little main line running. No continous running.

Recommended mainly for medium or large layouts, or for a small layout where the terminal is the whole layout, perhaps combined with a removable sector plate.


The third is "dogbone".

Pro: Permits lots of mainline traffic to be run, as there doesn't have to be on-layout destinations for any trains. As the trains are easily turned, it's suitable for for very  dense traffic.

Con: Takes up a lot of space if you want to have much of the mainline visible.

Recommended if you have plenty of rolling stock and want to run many different trains. Making room for two reversing loops is a headache in small spaces.


The fourth is the good old oval layout.


Pro: Can be built very compactly. Has continous run capability. Lap running can make the single station do the job of two or more. Can be built either with lots of scenery or lots of track. Can easily be extended, either with more tracks in the same space or with an addition.

Con: Doesn't look very realistic, does it? So one stretch of the mainline has to be hidden, either in a tunnel or behind a forest or buildings.

The type of layout I recommend, unless you know must have an other.



How large?


In one word: Small.
Or at least: Start small and plan for extension of the layout.


Many people who start out with a large layout as a first project find out that it's a much larger project than they thought, and never finish it. (Yes, I know some people say "A model railway is never finished", but take that to mean "There's always room for improvements" instead. Even if you have all track put down and operating well, you can always upgrade your scenery, rolling stock, buildings and so on.) Always having a half-finished layout isn't much fun.

A good way of measuring layout "size" is counting the number of turnouts on it. Too many and it's too complex, too few and it lacks in operating potential. As a beginner, you should aim for between 10 and 20 turnouts, money and space beeing the deciding factors.

In H0 this can be just right for a layout from 1.0 m x 2.5 m to 1.4 m x 4.0 m.



What type of railway should the layout try to be

Since we have determined that this is to be a small layout, modelling the operation on a large main line is not very feasible. (There is a very good layout of that type at Tekniska Museet in Stockholm , but since it's got nothing but main line, it would be too boring to run for most of us. A small narrow gauge railway would be a good choice for many of us, but due to the lack of availability of equipment I can't recommend that for most of us. At least not at present.

My preferred choice is a standard gauge short line, or branch of a major railway. That way you can run small locos, steam or diesel, and almost any type of freight car can appear on the layout. And it will all look reasonable.



Track arrangements


No unnecessary turnouts

Get rid of all unnecessary turnouts! Real railways only
install them when they need to, as they cost money. On
a model railway, you have the added advantage that any
removed turnout makes room for other things, like track,
buildings or scenery.



Two track configurations

The upper arrangement has one switch lead and one track to store cars on during switching operations. That makes it all too easy for you as an operator: Use the main line instead for those functions, like in the lower arrangement. Yes, it will block the main line, but on a small layout you can't make switching too easy, because then it's not enough fun to operate.


Two track configurations

You do not need two tracks to service two industries. By having them both on the same track you can reduce the number of turnouts and you create more operating problems for yourself, both good things.
When the industry tracks are short, like about two cars (or less), the turnout itself takes up so much room that by removing it you free so much space that you can actually fit in more cars in about the same area.


Two track configurations

This is also very much the case regarding engine houses. Having a turnout and curve in front of a two stall house makes it take up much more space than a single stall house, with an isolated section in front of it, that the disadvantage (if it is a disadvantage) of parking one engine outdoors is very small indeed.


Avoid straight and parallell tracks

Two track configurations

As much as possible, avoid having your track parallell to the edges of the benchwork. It will require a little extra space, but as you see in the lower example, it will look less regular and much better. It will also give you better space to lay spurs off the main line. By not making the track absolutely straight everywhere it can be, the layout will also seem larger.



No "S" curves


Two track configurations

If you go directly from a left to right curve, like in the upper example, the risk for derailments increase. Even if your present rolling stock will handle the S curve you're planning, you can't be certain the equipment you'll get sometime in the future will, so try to have about a car lenght of straight track between curves. (If the curves are very large radius, it might not be neccessary, but such curves probably won't fit on a small layout.)


Use large radius curves

Whereever you can, use as large radius curve as possible. Even if you can't use large radius everywhere, their use in some places can improve the layout by a great amount, as it will look much nicer. (Note: If you use flex track -- something I do not recommend to beginners -- be careful so that there aren't any small sections, "kinks", in a curve where the radius is smaller than the minimum radius for the layout!)


Two track configurations

In general, you should try to mimic real railways' curves where
the beginning and end of each curve is of much larger radius than the central part (and sections in between are of intermediate radius). This will make the track seem to flow much smoother over the layout and make the movements of the trains seem less "jerky", like it would be if it followed the dotted track, where the curves are perfect circles.



Two track configurations

In practice, this is of course hard to do on a small layout, so what you should do is to use the large radius curves where they will have the greatest visual impact.

In general, where the viewer sees the inside of a curve, it can be tighter, so I recommend that you use different radius curves like this, with the larger radius curves near the front of the layout, where you'll see the outside of the train as it goes through the curve.


Beware of grades!


My most important advice on grades is: Avoid them totally if you can! What you should do instead is to let the scenery be at different altitudes, so the track sometimes runs in a cut, sometimes on a fill.

If you cannot build the layout you want without using grades, be careful. On a model railway, we can usually get away with much, much steeper grades than the prototype. But the grade isn't what causes most problems: It's the vertical curves that are problematical. The beginning and end of each grade should be as gradual as possible, with large vertical curves!

This means that when designing a track plan, you cannot just use the grade expressed in % to figure out how long a track must be in order to pass over another track, you have to add a large amount for the vertical curves. For the size layout I'm envisioning,
you won't have the space for such long grades, unless you choose a complicated track arrangement.


Bottom of grade

When you compare these two grades, you see that they both have the same inclination, and yet the lower one is much more likely to cause problems than the upper one. The reason is that when a loco or car enters the lower, small radius, vertical curve, wheels towards the
centre tends to lift off the track.

For a loco this means a reduction in traction, for cars an increased risk of derailing.

Top of grade

Turning the image upside down, you see that the same reasoning holds on top of the grade.


And just as with horizontal curves, it doesn't matter if the total curve radius is large if there's a small section with a small radius curve.


What sort of tracks do you need?

In order to get a reasonable interesting operating potential, you should have at least four tracks, or "destinations". (More is better, but don't crowd it!)

I recommend that three of them should be general purpose tracks, so any type of car can use them, for example:

  1. Quay. Anything can come and go on ships.
  2. Team track. If the customers come to the railway with their goods, it can be  anything.
  3. Interchange. This is where cars go "off and on" the layout. Can be either a fiddle yard where you do it by hand, a set of hidden tracks where you drop off and pick up cars or a full blown staging yard.
The fourth should be connected to an industry of some kind, so there's an obvious,  visible purpose to the cars there. Some examples are:
  • A mine. Empty hoppers in, loaded hoppers out. Sometimes a boxcar with supplies arrives.
  • A sawmill. Flatcars with logs in, boxcars with finished products out.
  • Petroleum terminal or chemical industry. Tank cars out and in.

What rolling stock is needed?

Not much, really. To start, abide by the "Rule of Threes": As long as you have at least three of  something, it will seem like "many", as the total space and number of objects is relatively low.
Plan on having at most three locos: One running, one parked, one on "off line maintenance". You'll need at least three types of freight cars, but except for one type, you'll need only one or two examples of each. The class of cars that goes to the dominant industry should have at least three examples, so it's obvious they are "many".
One loco, two passenger coaches, seven freight cars of three types and a small layout like this is almost at capacity. Count the number of cars you could park on all spurs, and never exceed 60% of that number on the layout at the same time! If you think it's too little variety, have them exchanged via the interchange.

Much of the inspiration for these recommendations come from articles by Hans Svensson in the magazine Allt om Hobby.


Text last updated 1995

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