The following is based on Fallout Tactics and some details might contradict canon.
The tank track robot was a utility robot used in agriculture before the Great War. After the War, it was adapted by the Calculator, the mad cyborg from Vault 0, for close range combat.
It attacks using its spinning flails which can deal a great bit of damage. Though highly resistant it can be easily defeated because it can't fit through most doorways, lacks a ranged attack, and takes time to spin up its flails, making it fairly easy to maneuver away from before it can do any damage.
