For heavy passenger and freight trains, the SJ ordered ten 4-6-0 locomotives from Richmond Locomotive Works, since the Swedish builders were busy at that time. They were two-cylinder compounds with a saturated taper boiler. Boiler pressure of these first ten was 180 psi or 12.4 bars. Between 1901 and 1905, 29 more were built by NoHAB and 14 by Motala Verkstad. These had a boiler pressure of 13.5 bars. The designation of this class was T. After the introduction of the Tb with a larger boiler, the T was renamed to Ta. In the twenties the Ta received parallel boilers to make them as powerful as the Tb. But withdrawals already started in 1927 and by 1942, only four were remaining.

Some were sold to the Finnish State Railways after their withdrawal to address a severe locomotive shortage in World War II. There they had to be re-gauged to broad gauge and needed more modifications before they could be used as Hr2. After the war, they were used for some more years and scrapped between 1950 and 1953. The four locomotives still in service in Sweden again became the T in 1942, while the Tb became the T2. Since both now had similar boilers, they were combined to the new class B5 in 1952. The last ones were scrapped in 1964.