The biggest challenge in building any yard is design. It is easy to fall into the trap of assuming more is better. Classification yards are for sorting not storing cars. While capacity is important, you want your yard to be functional. Most classification yards are really several yards in one.
- Arrival / Departure Yard(s): These tracks are used by arriving and departing trains, allowing incoming trains to be held off the mainline until classification takes place. Locomotives and cabooses are removed / added here. If trains are only setting off or picking up solid blocks of cars, some of that work may be done from here. In larger yards, arrival and departure tracks are separate, but they can be combined to save space.
- Classification Yard: This is the heart of the yard, where trains are sorted by destination into new blocks. These blocks can then be combined in the departure yard to form new trains. The classification yard can be flat switched or may use a hump to speed switching. It may have switch ladders at one or both ends.
- Yard Lead: In order to classify cars, crews need a clear track from which to work. The yard lead adjoins the ladder of the classification yard. This keeps all of this action off of the mainline. Ideally, this track will be at least as long as the longest track in your yard.
- Through Yard: Some trains may not require any switching at all. A mainline bypass for trains that don't stop, or a storage siding or yard for trains that only change crews or locomotives keeps this traffic out of the gridlock.
- Auxiliary Services: Most yards also have several other dedicated areas not related to classifying freight. These include locomotive, car and track service and repair facilities, offices, ice houses for restocking refrigerator cars, cattle yards for resting livestock, express facilities for LCL (Less-than-Car-Load) shipments, storage tracks for seasonal or excess cars, or local yards for marshalling cars for industries located near the yard.
You may not need all of these elements, but the first three are essential for smooth operations. Tracks can be arranged in many ways to fit the space you have available. But before you start laying out a plan, there are some important questions you need to ask.
- How many classification tracks to I need? Most operators assume you need one track in your yard for each destination, but this is not necessarily true. Only destinations that will receive large amounts of cars really need their own track. Perhaps some classifications can be moved to another yard. Smaller destinations could share a track and simply be switched twice. Tracks also do not need to be dedicated to a specific destination all the time.
- How long should the classification tracks be? This really depends on how many cars you plan to switch into each track. If you plan to run twenty-five car trains, and you hold an entire train's worth of cars on one track, then that track needs to be at least twenty-five cars long. Of course you could also use two thirteen car capacity tracks if you have a wider but shorter footprint.
- How many arrival / departure tracks do I need? Most yards will need at least two tracks for arrival and departure. This allows multiple functions to happen without holding up the mainline or the classification operations. Larger yards may require more. Arrival / Departure tracks should be as long as the longest train you plan to classify. You can combine arrival and departure in one area, or provide separate yards for each. On a hump yard, the arrival yard typically adjoins the classification yard and can double as the yard lead.
- Single-ended or double-ended? Most prototype yards have switching ladders at both ends. In other words, tracks can be reached from either side. This is the most efficient switching arrangement when two or more crews are available. On many model railroads, especially if only one person will be working the yard, a lot of space, money and time can be saved by only allowing one way in or out.
- How long should my lead be? The longer the lead, the more cars you can shift in a single cut. If you are using a single-ended classification yard, the lead should be at least as long as the longest classification track. This allows you to pull an entire track at once.
- Flat switch or hump? Hump yards have a reputation for being immense and complex. Some are, but railroads often use gravity to their advantage on a smaller scale too. With or without retarders and motorized turnouts, a hump yard will be a more complicated construction project. The effort pays off in an efficient yard that can be a lot of fun to operate. Flat switching has its own charms and fun too.
- Powered or Manual Turnouts? You can save a lot of cost by operating all of your turnouts manually. Switch motors allow you to line a track with the push of a button however. If you are using manual turnouts, the design of the ladder becomes more important. Make sure you can still reach all of the turnouts without reaching over trains on neighboring tracks. Let the size and complexity of your operations and personal preference be your ultimate guide.
- Where should I place uncoupling magnets? If you use uncoupling magnets, they can be placed on each classification track for flat switching, or a single magnet could be used at the top of a hump yard. Always leave plenty of clearance at the end of your tracks when uncoupling cars.
Remember that even though they all do the same basic function, no two model or prototype yards are ever the same. The trick is to figure out how to arrange everything you want in the footprint available. Once you know how long and how many tracks you need, it is often easiest to play around with an assortment of turnouts to design a ladder that makes the most of your space.
Additional elements like servicing facilities, caboose tracks, etc. also need to be worked into the plan. Some of these can consume significant space of their own, but most can be manipulated into odd footprints much easier than the freight yards. Keeping some perspective is important. A yard that holds only thirty cars probably doesn't need a fifteen-stall roundhouse.
There is no right or wrong way to build a yard. You just have to build the right yard for you.