You may want to consider number tags. Number books can be purchased at the local big box stores. White band has a number on each wire in this bundle, pulled over-top of a ceiling, one section of the layout, to another remote section. White and black wires are track circuits. Brown 18 gauge solid thermostat wire is for switch control. Atlas 6924 relay boards and all associate switch input and output. Some of the thermostat wire is dedicated to accessory power.