The Tanzania-Zambia railway now bisects the Magombera Forest Reserve in Tanzania, and as a result the most viable surviving population of the rare endemic Iringa red colobus is seriously threatened. The railway has facilitated tree-felling, settlement and cultivation, and the colobus habitat is already seriously damaged. The authors conducted a survey of the forest in 1979, and recommended that the southern part, which has a viable colobus population, be included in the neighbouring Selous Game Reserve, thus giving that part the stronger protection of a game reserve, and that the local people be compensated by the release to them of a small area of the Selous.