Siding track

To park rolling stock or engines until needed.

Welcome to the world's greatest hobby!! You're in a great place to find answers to your questions.

Sidings are a great way to upgrade a basic loop of track. You can add a spur using one switch which is essentially a dead-end track for parking a train when not in use, or you can add a "passing siding" using two switches.

Sidings can be used for many things:

Spur sidings (switch on one end bumper at the other) can be used for parking additional train cars and locomotives or to allow a train to service an Industry off the main line.

Passing sidings (with switches at both ends) can allow two trains on your main line to pass each other.

A combination of these is typically referred to as a Yard and can be used to store and assemble/disassemble Consists (the cars and Locos that make up a train.

If you are simultaneously running more than one conventional loco (throttle controls provided by handles on transformer(s)), the sidings would need to have the center rail electrically isolated from each other and  from the main line and each controlled independently.  If you're only planning to run one conventional loco on connected track, or use Lion Chief Remote control, then all track sections may be all interconnected electrically.

Of course there's a bit more to the electrical part, but that's an answer to your question.

Sidings access different sections of the layout.  This grain elevator, an example.

The coal tipple has three sidings.

Thanks answered both the spur and passing siding

Thanks all very helpful

A siding is also a great place to add operating accessories to your layout. They can add fun and excitement to any operating session

Sidings are where you hide the new train cars your significant other doesn’t know you bought

that’s why most are hidden tracks😁🚂