Excavator Tracks (Polygon mesh 3D model) is available on CGTrader for $29. Original author: 3D-Horse. Specs: 736357 polys, 753791 verts.
OBJ (OBJ, filesize: 18.9 MB), 3DS (3D Studio, filesize: 7.87 MB), C4D (Cinema 4D, filesize: 3.03 MB), LWO (Lightwave, filesize: 6.51 MB), MAX (Autodesk 3ds Max, filesize: 13 MB), MA (Autodesk Maya, filesize: 9.43 MB), HRC (Autodesk Softimage, filesize: 5.97 MB)