Milecastle 48 (Poltross Burn) is the most thoroughly explored and best preserved, but one should be wary of regarding it as typical. It had two internal buildings, one on either side of a road leading between its north and south gateways. In the north-east corner was a staircase leading up to its rampart walk and, in the north-west, an oven for cooking. Other milecastles show similar, but not identical, arrangements, with a central road and a building on either or both sides of it. It is generally supposed that the structures provided accommodation for a small garrison, which it is presumed was outposted from the nearest fort.