The Belgian State Railways Type 1 was a class of 2-4-0 steam locomotives for passenger service, introduced in 1864.

[3] On the earlier series the suspension had simple balancing levers between the driving wheels.

The engines built by Couillet and Schneider in 1867–1868 used a doorbell mechanism instead of the balancing lever to equalize the suspension forces between the two driving axles and on the last series in 1882 balancing levers between the leading axle and the first driver were used, combined with larger leaf springs on the rear driving axle.

The locomotives also received new boilers and new cabs on major overhauls beginning with 1889.

[1] With the advent of the Type 12 in 1888 the machines were deployed to secondary lines.