In the last H9 order from the Berlin-based manufacturer, Schwartzkopff, in the spring of 1920 it was decided to provide the engines with Knorr feedwater pre-heaters and larger eight-wheel bogie tenders. Otherwise, they were identical to the earlier class H9 locomotives and both versions bore the same H9 classification. It was only in the 1942 re-classification that the class was divided: class Hv2 with six-wheel tenders and class Hv3 with eight-wheel bogie tenders.
The order from Schwartzkopff was completed in 1921 and numbered 638–647. The following batch was an order for five H9s from Tampella in the spring of 1932, numbered 781–785; these were completed during the same and following year. The class was further increased with an order for nine placed with Lokomo in 1937 and 1939, completed in 1938–41, and numbered 991–999. Classes H9 / Hv3 comprised twenty-
four locomotives.
The various batches had slight differences. Nos. 638–647 had a boiler pressure of 12kg/cm2 whilst nos. 781–785 and 991–999 were pressed to 13kg/cm2. Thus, the last fourteen engines had a greater tractive effort than the earlier members of the class as long as the boilers were not exchanged. Nos. 781–785 were equipped with Friedmann-Metcalfe exhaust steam injectors instead of Knorr feedwater pre-heaters. Nos. 638–647 were gas lit at first. Nos. 781–785 and 998–999 had a central lighting system for the train and engine while nos. 991–997 had electric lighting for the locomotive only and were equipped with larger headlamps like 998–999. Nos. 638–647 were built as wood burners while nos. 781–785 and 991–999 were built for coal firing. The tenders attached to nos. 991–999 had slightly higher sides than their previous Hv3 counterparts, and the fireboxes of these latter engines were made of steel instead of copper.
Various modifications were made to the class over the years. The permissible speed was raised from 80km/h to 95km/h in 1934. Nos. 638–647 received AGA lighting during the 1920s, then electric lighting between 1948 and 1949. Knorr feedwater pre-heaters were replaced with Friedmann live steam injectors between 1952 and 1954. Lentz valves, fitted in place of ordinary piston valves, were tried on nos. 784 and 785 between 1937 and 1939, but these experiments failed to meet expectations and ended with the outbreak of the Finnish Winter War in 1939.
Nos. 781–785 and 998–999 had their central train lighting systems removed between 1947 and 1949 to use electric engine lamps only. The Hv3s were altered many times between coal and wood burning. An iron framework was added in the 1950s to heighten the tenders of nos. 638–647 and 781–785, increasing the fuel capacity. No. 640 (like Hv2 no 777) was equipped with a tender with higher water capacity, enabling the engine to run between Pieksämäki and Haapamäki without a watering stop. Because the Hr1
class engines were already expected to take over the express turns on the line, no more Hv3 tenders were rebuilt. The boilers for all H9s were interchangeable but, apart from odd exceptions, the boilers with higher working pressure were retained for use with nos. 781–785 and 991–999.
Class H9 nos. 638–647 entered service at Viipuri but were transferred to Kouvola and Pieksämäki in 1929. A few of these were mobilised to Äänislinna in Eastern Karelia between 1942 and 1944 during the Finnish Continuation War but were then reallocated to Pieksämäki. Nos. 781–785 worked out of Tampere during trials, then were transferred to Helsinki in the summer of 1933. This batch was also used during the 1940s and 1950s at Turku, Helsinki and Tampere. Their last years of service were at Kouvola and Joensuu. Nos. 996–999 were first tried out at Tampere before going on to Helsinki, with two later being transferred to Viipuri. They were shedded at Turku, Helsinki, Kouvola and Sorta-vala during the war, following which they were mainly at Seinäjoki for express and passenger trains to Oulu and Vaasa. Nos. 991–995 were transferred via Tampere and Kouvola to Sortavala, and used there between 1942 and 1944. In the post-war years they worked out of Kouvola until 1960 and, finally, Seinäjoki.
The H9/Hv3 class engines were initially used on the principal express duties but later worked other semi-fast trains Because their tenders were bigger than those used by the H8/Hv1 and H9/Hv2 classes, they could undertake longer journeys without water and fuel replenishments.
The introduction of the Hr1 class affected the Hv3 class the most. As the 4–6–2s then dominated the heavily loaded Helsinki–Tampere and Helsinki–Kouvola expresses, the Hv3s were then cascaded to other routes. Encroaching dieselisation gradually diminished the use of the Hv3 locomotives altogether, their duties coming to a conclusion in 1970, the final turns being between Savonlinna and Parikkala.
The older Hv3 class members, nos. 638–647, were withdrawn in 1965 and scrapped whilst nos. 781–785 and 991–999 were stored for the eventuality of national emergencies. In 1977, all were condemned for scrapping with the exception of three preserved ones.
Classes Hv1, Hv2 and Hv3, with a combined total of ninety-nine locomotives, handled the main passenger rosters until full dieselisation of the VR. The numbers built and their longevity bear witness to the fact that they were one of the most useful types of locomotive ever to be found on the VR.