Compression: Why it's evil, and why you need it

At this point I'm going to focus on the bad word:  Compression. Compression is going to be the watchword throughout the design process.  It is our evil but necessary friend.  Why, you ask?

We can't hope to include a true scale model of almost any yard on our layouts any more than we can expect to have more than a few scale miles of track to represent a division of 100 or more prototype miles.  Something has to be left out (for the railroad, usually the long, boring miles in between interesting spots) in order to fit it into the average layout room.  Yards are no different -- they are big places with miles and miles of track, which we can't hope to model in its entirety.

Real classification yards are huge, often consisting of many smaller special-purpose yards that make up the whole complex.  A common plan uses three separate double-ended yards strung one after the other to move traffic efficiently:  an arrival yard, a classification yard, and a departure yard.  As might be expected, an arrival yard is where arriving trains drop off the cars of their train.  They are picked up there and moved to the classification yard, being switched back and forth as necessary to get the right cars onto the right trains.  As the trains are built out, they are moved to the departure yard, where they get a new caboose and locomotive and proceed to their next destination.  Often an identical set of yards will exist on the other side of the main, serving trains moving in the other direction.

Since (almost) no one can model this, it's necessary to compress the essence of the operation down to a manageable and modelable level.  What most folks do is compress the three yards into the space of one, forcing one or two tracks to do the work of many miles of prototype track.  As you might imagine, this makes for a lot of pressure on the people you choose to operate your yard.  They will often have to do nearly as much work as a prototype crew to get through a session.

How Model Train Classification Yards Work

Most model railroaders have far more cars (rolling stock) and locomotives than they can possibly operate at once. One option is to simply store excess rolling stock and locomotives in boxes or on display shelves or cabinets. It is possible, however, to store all of your extra equipment and trains on tracks in a yard that may or may not be part of the visible operating portion of your model train layout.

However, design mistakes are a common feature of model railroad yard layouts. Yards don't always work out as well as they should. A major cause is the lack of available information on how to design a good model railroad yard layout. Without the resources, model railroaders are forced into a lot of guesswork.

Model Train Yard Layout Compression

Apart from the lack of available information on model railroad yards, another cause for less than satisfactory model railroad yard designs, is the need to compress a model railroad layout into the space available. 'Compression' is the model railroaders enemy, but in most cases, necessary.

Let's start by looking at the make up of real classification yards. Generally, they are huge. They often consist of many smaller special-purpose rail yards, that collectively, add up to a complex array of train track.

It is commonplace for there to be three separate double-ended rail yards strung one after the other. These are designed to move train traffic efficiently and usually comprise: an arrival yard, a classification yard, and a departure yard.

The Arrival Yard On Model Train Layouts

The arrival yard is where arriving trains drop off the cars of their train. The cars are then moved to the classification yard, being switched back and forth as necessary to get the right cars onto the right trains. The trains are then built out and moved to the departure yard. After getting a new caboose and locomotive, they then proceed to their next destination.

For more information on yard designs read the best-selling Model Train Help ebook by Robert Anderson (Highly Recommended).