Overhead Pole

A single-track catenary pole. Place it beside the track; it serves as the base on which you mount a Wire Insulator to then string Wire.

Placement

Hold the overhead pole from your inventory and right-click the top face of the ground or a block where you want it to stand.

The orientation is chosen automatically to match the track angle (8 directions, 45° steps). Used beside a track, it naturally aligns parallel to the rail.
To add height: right-click the top of a pole that is already standing, and another pole of the same orientation stacks on top. Keep right-clicking to raise it higher and higher.
For evenly-spaced bulk placement, the Overhead Pole Auto Tool is handy (bulk-places poles, trusses, and insulators along the track at your configured height and count).

Place overhead poles beside the track and stack them to the required height.
Right-click to place a Wire Insulator on the top face of a pole.
Place an insulator on the neighboring pole the same way.
Put the Wire Connector Tool into placement mode and right-click insulator → insulator in order to string the wire.