These 1B1-tender locomotives were the first of this class in The Netherlands, in fact the NRS employed the first passenger service tender locomotives with this type. The Westinghouse brake system was a first for the NRS; the additional hand brake was common. To obtain a stable ride at high speeds, inside cylinders were employed. The firebox was situated between the coupled axles. The front and rear axles were of the Webb type, already employed by the London North Western Railway. The radial axle boxes were produced with very fine tolerances. Rubber bumpers were employed to move the axle back into position.