The Queensland Railways A12 class locomotive was a class of 4-4-0 steam locomotives operated by the Queensland Railways.
Between 1882 and 1895, the Queensland Railways took delivery of 43 4-4-0 locomotives built by Baldwin Locomotive Works (18) and Evans, Anderson, Phelan & Co (25). Per Queensland Railway's classification system they were designated the A12 class, A representing they had two driving axles, and the 12 the cylinder diameter in inches. An American built A12 class locomotive No.62 boiler exploded at Roma Street, Brisbane on 2 December 1898. The Court of Enquiry into the explosion was recorded in the 1899 Votes and Proceedings of the Queensland Legislative Assembly.