During the construction of the Bernese Oberland Railway (BOB), it was planned to purchase one type of adhesion locomotive for the less steep section and one type of purely rack locomotive for the steeper section. By the time the line opened in 1890, the decision was made to purchase only one type with a combined adhesion and reck drive. The first three HG 3 were delivered in 1890 and three more in 1893. They later became HG 3/3 according to the Swiss system.

These were 0-6-0RT tank locomotives and had outside frames. The rack drive was mounted on the driving axles to avoid problems with the suspension. Of the two rack gears under the locomotive, one was used for driving and one for braking. The boiler was inclined by five percent compared to the frame.

After the BOB was electrified in 1914, these locomotives were no longer needed in daily operations and five of them were sold. Three were converted from the gauge of 1,000 mm to 950 mm and sold to the Italian Mediterranea-Calabro-Lucane. Two went to the Arosa Railway, but were sold to industry after a short time. The sixth locomotive remained with the BOB as a reserve.