To obtain a stable ride at high speeds, inside cylinders were employed.

The front and rear axles were of the Webb type, already employed by the London North Western Railway.

A second series of the same type of locomotives was ordered by the Nederlandsche Zuid Ooster Spoorweg Maatschappij (NOZS).

Initially, six engines were ordered for service on its Nijmegen-Den Bosch-Tilburg route; later another two machines were added.

During their later operating years, some engines got outfitted with serve-pipes which put the heated surface to 107.5 m2 or 89.5 m2.