Hollow carriages are functionally similar to frame carriages, in that they carry all adjacent blocks when moved. They may be interchanged with ordinary frame carriages; no adapters are necessary. They support ForgeMultipart and can be placed over wires or microblocks - note that they must be placed after all other parts.

They are crafted by placing 8 frame carriages in a crafting table, leaving the middle empty. They can also be converted back to ordinary frame carriages by placing them in a crafting table.