A rail yard is a network of tracks for storing, sorting, loading, and unloading rolling stock and locomotives. One of the most distinguishing features of a rail yard is long stretches of parallel track used to store rolling stock off of the main line. Specially designed locomotives, called switching or shunting engines, are used to move cars around and attach and detach them from trains. These engines are optimized for the job of getting individual cars moving and stopped quickly.
A yard typically has several of the following components:
Yard components can also be described by their geometry. A stub yard is a yard layout with an egress on only one end, which a typical configuration for a switching yard. In contrast, a through yard connects on both ends. This is a common configuration for receiving and departure yards, but it is also used in switching yards as well.
Because yards have so many elements even a simple configuration can take up a great deal of space. Indeed, one could very easily fill an entire table with just a classification yard, and consume a half a dozen L and M switches in the process. Add a roundhouse, turntable, engine shed, and other accessories, and one could conceivable build an entire two or three table layout that was nothing more than a yard! So obviously some simplification and compaction is necessary, particularly if you are limited in space, track, or both.
That being said, even a simple yard is going to take a lot of track, and in particular a lot of switches. This is the one place where I recommend you have specialty pieces, and possibly some third party track to help you along. Here's what should be in your toy box:
Some common constructions for a stub yard using BRIO track are below.
This is the most basic configuration, using three curved switches (in this case, 3 x M) to form three spurs. Keeping all of the branches to an identical length is not really possible, something that will become a problem later on when we discuss through yards.
An alternative arrangement is to split the middle branch into two branches. This does not change the total area needed by the yard, but it does alter length and spacing of the first two sidings. This approach of making a branch off of the main artery of the yard and splitting it again is fairly common in real switching yards.
If space is absolutely at a premium, then you can use the short cuved switches O1 and P1, and the short curve E1 to make the yard more compact.
The geometry of through yards can be problematic because you have to make multiple sidings split and then rejoin. While the Vario System can generally soak up small differences in track lengths, when you make multiple joints you end up forming a far more rigid structure. Imprecise alignments that can be ignored in typical BRIO layout quickly become huge problems in a through yard, as you can no longer force the track to fit.
The layouts presented so far have all used genuine BRIO track, but when it comes to through yards the use of third party track simply cannot be avoided. Even if you are fortunate enough to possess some of the rare A3 pieces, the slightly longer Jesse's Toy Box 3" straight, and longer still Maxim 3" straight, are necessary components.
Another problem with through yards is simply the space required. If you want more than one or two sidings, you are going to need a lot of room.
Changing from L and M switches to O1 and P1 switches does compact the layout.
BRIO created a simpler, smaller version of a through yard in its vintage sets, such as this configuration from the 1987 starter set #33143. It uses Ex2 + Dx2 in the siding, and A + Dx2 in the main line.