RM Class 4-6-2s
The RM was China's last steam passenger design. It was a late 1950s development of the successful pre-war SL6 pacific, which was adopted as the standard passenger class post liberation. The new locos employed a Russian style boiler, similar (if not identical) to that used by the JS 2-8-2, mounted on a rolling chassis based closely on the SL6 design. Many parts were designed to be interchangeable with the JS class. The first RM entered service in 1958 and a total of 258 were built before production ceased in 1966. The vast majority of locos were built in the early years with around 250 in service by 1961. The RMs were numbered RM 1001 to 1258 to avoid overlap with the various SL classes.
RM 1060 was one of a small fleet which handled many secondary passenger trains around Changchun in the late 1980s. The loco is seen here at Changchun depot between duties in March 1989. Just over a year later, none were left in traffic.
The RMs weren't particularly large or powerful locomotives and, as passenger train lengths increased in the 1970s and 1980s, they were displaced from premier services by locos more suited to handling heavier trains. Many were replaced by diesels, such as the BJ or DFH3 classes, which were specifically designed for passenger work. Others gave way to QJs, a class incapable of true express passenger speeds but capable of moving heavier loads reliably. Most RMs worked out their last years on secondary passenger duties. Xi'an was famous for it's concentration of RM's in the early 1980s but the class's final fling was in Manchuria, where they could be seen around major centres such as Shenyang, Changchun, Harbin, Qiqihaer, Mudanjiang and Jiamusi.
The last RMs were withdrawn from Changchun and Jiamusi depots in early 1990. The final survivor was RM 1183, which was reported in traffic at Changchun in June of that year. Ironically, the RMs were outlasted by their predecessors, the SL6 class, a few of which continued in service until 1991. As far as is known, no RMs went into industrial or local railway service but two have been preserved, the pioneer, RM 1001, is in the Beijing Railway Museum and RM 1163 is at Aioi, Japan.
The RMs' early demise was inevitable as train weights outgrew their capabilities but it could have been so different. In the 1950s Dalian produced a design for a 4-8-4 passenger loco with Soviet assistance. Little is known of this loco but it was almost certainly based on the Russian P36 Class. Unfortunately, none were ever built. Had this design been produced instead of the RM, steam could have continued in top link passenger service for a few more years.