Devices, systems, and methods are provided for compact transmission lines structure. A compact transmission lines structure may comprise a first subsystem of a pole and a crossarm, wherein the crossarm is stacked above the pole, wherein the crossarm comprises a cantilever end situated away from the pole. The compact transmission lines structure may comprise a second subsystem connected to the cantilever end. The second subsystem comprising a first diamond-shaped insulator assembly supporting a first single three-phase transmission line. The compact transmission lines structure may comprise a third subsystem connected to the cantilever end, the third subsystem comprising a second diamond-shaped insulator assembly supporting a second single three-phase transmission line, wherein the second diamond-shaped insulator assembly mirrors the first diamond-shaped insulator assembly. The compact transmission lines structure may comprise at least two shield wires configured to provide lightning protection.