Finland saw a notable boom in rail traffic in the late 1890s, resulting in greater loads being hauled. This was especially true of passenger traffic, for which the A class 4–4–0s were increasingly inadequate. In 1897 larger and more powerful passenger engines were ordered from Baldwin because European manufacturers were unable to produce the required engines by the desired delivery date. The fast schedule determined that the locomotives were to be built in the American style, for instance with bar frames instead of the more traditional plate frames. A batch of ten locomotives was to be shipped to Hanko harbour by the American manufacturer as soon as April 1898, the locomotives being operational by the autumn of the same year, classified H1 and numbered 232–241.
This six-coupled design with a pivoted, swinging front bogie became standard for the state railway passenger classes over the following forty years. The simple expansion engine had bar frames, a saturated steam boiler, Stephenson inside valve gear and, initially, slide valves. The lamps were gas lit. Nos. 232–241 were built for coal firing but later the engines alternated between wood and coal according to the cost and availability of fuel. In 1930–31 peat-burning was also tried out on nos. 232 and 233. The six-wheel tender had a fixed front axle and a rear four-wheel bogie.
The Kylälä blast pipe was experimentally fitted to no. 239 in 1918. In the 1920s the class was superheated and the slide valves were replaced by piston valves by adding valve chests above the cylinders. During trials, speeds in excess of 100km/h were attained but the maximum permitted speed was fixed at 80km/h, the maximum on the SVR/VR until 1934 when it was raised to 95km/h (85km/h for classes H1–H7). Aga gas lighting was installed in the 1920s.
On their introduction, nos. 232–241 were dispatched to Helsinki, Viipuri and Riihimäki loco sheds but they were later in use at St Petersburg, Kouvola and Karjaa, mainly for passenger rosters. Transfers took them to central Finland. The Hk1 class locomotives from this batch to remain in Finland following the Second World War could be found at Seinäjoki, Karjaa, Riihimäki and Helsinki.
At the end of hostilities in 1918, no. 232 remained behind on Soviet territory but was redeemed in 1924 and returned to traffic in 1925. No. 233 was withdrawn in 1937. After the Winter War nos. 232 and 234–237 were ceded to Soviet Union. The remaining four locomotives were reclassified Hk1 in 1942 and they were withdrawn as late as 1956–59.