An interchange is a place where two or more railroads connect and can exchange traffic. Interchanges enable goods picked up on one railroad to be delivered on another without being reloaded. It also explains why you will see freight trains with cars from many different companies on the same line. An interchange may only see a few cars change hand a week, or it may be a major connection where entire trains pass from one railroad to another.
For modelers, an interchange is an easy way to increase the prototypical operations of your layout. Because almost any type of car can show up on an interchange, these can function as a "universal industry" that can receive or originate unlimited traffic variety. An interchange can also be built with a very small footprint...just a small siding long enough to hold a few cars. Large or small, an interchange can extend the reach of your layout "beyond the basement."
Operating with an Interchange
Just like the prototype, there are lots of ways to design an interchange for your layout.
- Small Interchange. A small interchage with a shortline or industrial railroad may be modeled with only a short spur of track. Some modelers extend the spur to the edge of the platform to suggest that it continues beyond the modeled layout. Cars are set out and picked up from this siding as with any other spur.
- Interchange with Yard. Railroads will often locate a yard near busier interchanges. You can model an interchange operation without modeling the connection itself by dedicating a track in one of your yards to the interchange operation.
- Interchange with Staging. For larger operations, espescially when full trains are exchanged, modelers will often build a staging yard to accomodate the interchange traffic. A portion of the connecting railroad itself may even be modeled. An alternative to a full staging yard is removeable cases for storing cuts of cars. Modelers of waterfront scenes often model an interchange with replaceable barges of rail cars that can be physically removed from the layout.
Adding an interchange to your layout not only adds a lot to the operations, it can also add a lot of color as "foreign" cars and locomotives come onto the layout. Interchange trains, even with a short run, are often a favorite at operating sessions for this reason.