A Turnout (or Point or Switch) is an advtrains node that splits a track into multiple track (or combines two tracks into one).

A screenshot of a junction using Turnouts is below:

As you can see, there are many types of turnout. One type is a Y-turnout, which splits one track into two, one +15 degrees and another -15 degrees.

The second type is the straight turnout, which is accessible by left-clicking using the trackworker on a normal, straight track. This turnout keeps one track straight whilst adding/subtracting 15 degrees to another. You can see that 4 are used in the T-junction.

The third type, not photographed is the 3-way turnout, which acts like the y-turnout but with an additional third track in the middle for keeping straight.