The Belgian State Railways Type 12 was a class of 2-4-2 steam locomotives for express passenger service, introduced in 1888.

They were the successors of the Belgian State Railways Type 1 locomotives.

[1] The locomotives were built by various manufacturers from 1888 to 1897.

[1] The machines had an outside frame with the cylinders and the Walschaert valve gear located inside the frame.

[2] The locomotives used three-axle tenders with a 14 m3 (490 cu ft) capacity, as well as two-axle tenders with 9 m3 (320 cu ft).