K62-class locomotive

The M62 type was one of the most important types of diesel locomotive in the Comecon countries, with over 5,000 units being built for the railways of the Eastern Bloc, Cuba, Mongolia and North Korea.^[2] Initially designed to meet a requirement of the Hungarian State Railways,^[3] the reliability and the durability of the type helped it become a mainstay of many railways in the former Communist bloc. As it had done for many of those countries, the arrival of the M62 - or K62, as the units built for North Korea were designated at the factory - helped North Korea to significantly reduce its use of steam locomotives for mainline operations, and they played an important role in the DPRK's economic improvements of the 1960s.^[1]

Aside from the "K62" designation given by the factory, the Korean State Railway gave the type a unique class name as well: Sinsŏng. The class name, when written in Hanja, is 新星. In this case, these hanja are read as sinsŏng; however, there is a class of domestically built diesel shunters whose class name is written with the same hanja: the Saebyŏl-class (새별, "New Star").^[1] In practice this is not an issue, as the use of Chinese characters to write Korean is officially discouraged in the DPRK.

Although many types of diesel locomotive have been operated by the Korean State Railway over the years, the most important, in terms of both quantity and scale of operations, has been the K62-class, of which 64 units were built new for North Korea.^[1][4] These were built in two batches, the first being constructed between 1967 and 1969 (48 units), and the second batch of 16 between 1972 and 1974.^[5] Of the second batch, five were delivered in 1973 with 1,520 mm (4 ft 11+27⁄32 in) Russian gauge trucks for service on the Soviet-DPRK border at Tumangang.^[5]

Though plans were made to obtain 2M62-type two-unit versions of the M62, this ultimately failed to materialise;^[1] however, at least one twin-unit was delivered,^[4] whose remains have been seen, gutted and split in half - one section in P'yŏngyang, the other south of Mulgae on the P'yŏngbu Line to Kaesŏng.^[6]

In the early 1970s, the Kim Chong-t'ae Electric Locomotive Works reverse-engineered a Soviet-built M62. This led to the production of the Kŭmsong-class copies.^[4]

In 1998, the Kim Chong-t'ae Works began a project to convert M62s to electric operation, resulting in the Kanghaenggun-class electric locomotives.^[1] 21 Soviet-built M62s have been converted thus far, along with two of the Kim Chong-tae Works-built copies. These are used widely on lines such as the P'yŏngŭi and P'yŏngnam lines.^{[1][page needed]} The identities of the locomotives thus converted is unclear for the most part, but 632 is known to have been rebuilt into electric number 1.5-13.^[7]

The K62 class has been the backbone of diesel power on North Korea's railways for many years, being used all over the country, including on electrified lines.^[6] Because of their reliability and the crews' familiarity with the type, between 1996 and 2000 second-hand M62-type locomotives were bought from various countries. These locomotives were brought in from Russia, Germany, Poland and Slovakia, and were numbered variously in the 600, 700 and 800 series ranges.^[8] The locomotives purchased from Germany, Poland and Slovakia retain their European-style buffers, although the European couplers have been replaced with the Janney (AAR-type) knuckle coupler used by the Korean State Railway.^[6]

This series, numbers 내연601 to 내연665 is made up of the 64 units delivered new to North Korea from the factory,^[1] as well as one unit obtained second-hand from the Polish State Railways (내연665).^[9] 내연656 (works number 1384, built 1971), although built for the Korean State Railway, wasn't delivered immediately, instead having served for some years with Soviet Railways, assigned to the Lvov region as M62-1265.^[9] Some of the units originally built for the DPRK have since been retrofitted with exhaust silencers.^[6]

Some units of this series are being modernised, which includes the replacement of the original Kolomna 14D4 engine.^[9] The modernisation package includes replacement of the original engine with the new Kolomna 12ChN26/26 engine, and of the original 4-14DG generator with the new 5-26DG. These have a much lower fuel consumption than the originals, and can go longer before overhaul is required.^[10] In 2000, 내연604 was sent back to Luhanskteplovozstroi to undergo this modernisation, at which time it received a new blue and white livery similar to that used by the Russian Railways.^[9] Additionally, it received new headlights like those found on the Russian DM62 and M62U variants.

Since 2006, the new 12ChN26/26 engines and 5-26DG generators have been delivered to North Korea, the modernisations now taking place in domestic shops.^[10] So far, 내연602 - the machine inspected by Kim Il Sung and which carries plaques commemorating the occasion^[6] - is known to have been modernised.^[9] Locomotive 602 also has the distinction of having been the first North Korean locomotive to cross the Korean Demilitarized Zone since the end of the Korean War.^[11]

Almost all locomotives of the 600 series are painted in the standard blue over dark green livery, although there are a few exceptions. 604, as mentioned, was repainted into a blue and white scheme used by the Russian Railways. Several, including 622, 639 and 658 are painted in a scheme becoming more common, which replaces the blue in the standard livery with light green. 629 is overall dark green with a white stripe, and, as mentioned above, 656 still carries its Soviet paint and even lettering, while 653 has been repainted into the green and yellow scheme used on the 700 series locomotives. The one locomotive in this series that wasn't ordered new, 665, is one of the very few second-hand units that received the standard blue over green livery.

Known to be assigned to P'yŏngyang Depot are 602, 619, 620, 622, 625, 627, 638, 650, and 664.^[6]

One locomotive was rebuilt, likely after an accident, with new cabs similar to those on the Red Flag 6-class electrics locomotive, but with dual headlamps; this is numbered 내연001 and is painted in the standard livery.