Within half a year of taking office, Luršimonš set about providing the RSR with a goods engine to handle the steadily growing traffic. This, the first 6-coupled locomotive type in the country, was to prove long-lived and popular despite later developments. Borsig, of Berlin, delivered a first batch of twenty in 1858. The RSR, greatly pleased with its new acquisitions, immediately ordered a further ninety, also from Borsig. The class G took over all main-line goods work, being equally at home on the northern plains and in the southern highlands. They suffered, of course, from the usual shortcomings of long-boilers, their tail-wagging causing a number of derailments over the years. Displaced from the heaviest goods trains by the class M 0-8-0s of 1871, these 0-6-0s still found plenty of work on lesser duties, including a lot of branch-line passenger work. The class G lasted until the 1890s, when Belčamin's 2-8-0s took to the rails.

In 1861 two engines were fitted with boilers originally meant for class A2 2-4-0s. These then became class G1.