When British coal became more and more expensive at the beginning of the century, the Kazan railway administration was the first one to order a new locomotive that had a much larger grate than existing designs in Russia, enabling it to produce more power with low-calorific coal. These locomotives were intended for light, but very fast express trains. The requirements included a maximum speed of 107 km/h, an axle load of 16 tonnes, a superheater and two simple cylinders.

To create a large and wide grate, the new locomotive had to have a trailing axle. Since it was not possible to build a Pacific due to the limited length of turntables, a 2-6-2 “Prairie” was created. For better running characteristics while running forwards, the leading axle was connected to the first driving axle in a Zara bogie. The trailing axle was most likely an Adams axle. Since the first orders went to the Sormovo plant, this class became later known as C (what stands for the latin letter S).

On the level, they could haul 345 tonnes at 100 km/h, while the design top speed was 115 km/h. They hauled the fastest trains in Russia and sometimes even reached speeds of 125 km/h on short stretches of the line between Moscow and Saint Petersburg. Depending on the availability of other locomotives, they also often had to haul trains which were much heavier than intended for the class C. Withdrawals in larger numbers started in 1950 and were completed in 1964. Only C.68 was preserved and is on display at Saint Petersburg.