Androzani harvester

The Androzani Harvester was a three-legged alien machine used by the Harvest Rangers to collect trees. When harvesting a living forest, Droxil, Ven-Garr and Billis travelled in one. Madge Arwell used it to reach her children, Cyril and Lily. She crashed it. It was too badly damaged by acid rain to repair. (DW: The Doctor, the Widow and the Wardrobe)