All milecastles on the turf wall section of Hadrian's Wall were thought to have been constructed with turf ramparts, with a wooden tower over the north gate. There are no visible remains of Milecastle 50TW, however a corresponding causeway across the wall ditch is discernible; one of only two milecastles where such a structure survives, the other being Milecastle 25. A wooden culvert was initially used to allow water to flow beneath the causeway, but this was later replaced with a stone culvert.
