After the Class C with a 4-4-0 wheel arrangement and 6 ft 7 in wheels, the Shanghai-Nanjing Railway ordered four more locomotives that were to have even larger wheels. Using a boiler that was largely the same as that of existing classes of the company, one driving axle now had to be sufficient. Despite this, the boiler was the largest ever to be found on a British-made single-driver locomotive.

The engines were intended for express traffic as part of a large trade fair in Nanjing and should be up and running within 45 days of receipt of the order. Despite the national mourning for the death of King Edward and the Pentecost holidays, the time had come after 47 days. Their special position was underlined by the fact that they were painted in a bright yellow instead of the usual green.

Between 1956 and 1960, various factories in China manufactured a total of 42 prototypes of a new 2-10-2 freight locomotive, which was based on the Soviet ОР21. From 1964 onwards, series production of a total of 4,675 additional machines, which were soon referred to as QJ, began in Datong. The abbreviation here stood for “Qianjin”, which means “progress”.

They replaced the JF and FD in heavy freight service and also pulled heavy passenger trains. In addition to the stoker and mostly smoke deflectors, their features also included the distinctive air horn. Some QJs were also built in Soviet broad gauge. A chimney similar to the Giesl ejector was tested on other machines.

Although production continued until 1988, replacement with diesel locomotives began in the eighties. After steam operations on the Chinese State Railways officially ended in 2002, the last of them disappeared from the main lines in 2003. However, the private JiTong Railway used the QJ to transport coal on its 945 km long line in Inner Mongolia until 2005 and it was also used by industrial companies until around 2010. Three QJs later found their way to the USA.

A few years after the revolution, China Railway developed a Mikado that would be built in large numbers. The chassis of the JF1 class, which had been built since 1918, was used as the basis. It received a modern boiler and was also adapted to current requirements in other areas. The new class was called JS or “Jiàn Shè”, which roughly means “construction”.

With a coupling wheel diameter of only 1,370 mm, a high level of traction could be achieved. As is usual for China, the tender was chosen to be large with a coal supply of 17 tonnes. The design came from Dalian, but the production was subcontracted to several plants.

The first 1,135 units were built between 1957 and 1965. Another production only started in 1981, which included almost 800 more locomotives until 1988. More than half of them belonged to a “B” variant, which received some improvements. A special feature was a locomotive that was sold new in 1989 to the Boone and Scenic Valley Railroad in Iowa.

These Mikados were based on the JF6 and were developed for industrial tasks. With a construction period up to 1999, they were the last large series-built steam locomotives in the world. There are reports that some locomotives were still in use in 2016 in open-pit mines or in heavy industry companies. Accordingly, an extraordinarily large number have survived to this day. Between 1989 and 1991 three US tourist railways ordered brand new locomotives of this type, one of which was lost at sea. One machine was also delivered to South Korea in 1994.