After a number of incidents involving broken crankshafts in the Mikani class locomotives, as well as needing more motive power to meet the increase in goods traffic following the establishment of Manchukuo, the Mikashi class was designed in 1933[1] and put into production in 1935, with fifteen built in Japan that year, four by Kisha Seizō and eleven by Kawasaki.
As the three-cylinder design of the Mikani class was deemed too complex, the Mikashi class returned to the proven two-cylinder layout. In order to achieve a tractive effort equal to or greater than that of the three-cylinder locomotives with a two-cylinder engine, it is necessary to increase the adhesive weight of the locomotive; however, this would make the axle load unacceptably high - between 24.0 t (23.6 long tons) and 25.6 t (25.2 long tons). To overcome this, a limited cutoff system was adopted with a maximum cutoff of 50%; by balancing the rotational forces of the left and right cylinders, the axle load was successfully limited to 23.0 t (22.6 long tons).
Boiler pressure was increased from 12.7 to 17.0 kgf/cm2 (181 to 242 psi; 1,245 to 1,667 kPa), whilst other new features included a Schmidt type E superheater, a feedwater heater and a combustion chamber firebox. Fuel consumption was also improved, with the Mikashi class using from 10% to up to 22.6% less coal than the Mikani class. The wheel diameter was also increased from 1,370 to 1,500 mm (53.94 to 59.06 in) in order to increase the speed of goods trains, however as this could result in wheel slippage on steeper sections due to the reduction in piston speed, so the timetables of goods trains were adjusted accordingly. Used primarily on heavy goods trains between Fengtian and Dalian to transport coal from the Fushun Coal Mine to port, they could pull up to sixty 30 t (30 long tons; 33 short tons) coal hoppers.
At the end of the Pacific War, the 15 Mikashi class locomotives were divided between the Dalian (13) and the Fengtian (2) depots, and all were taken over by the Republic of China Railway. Following the establishment of the People's Republic and the subsequent creation of the current China Railway, they became class ㄇㄎ肆 (MK4) in 1951, and class 解放4 (JF4, jiěfàng, "liberation") in 1959 and numbered 2701–2715. As during the Mantetsu times, they were primarily used around Dalian and Shenyang (formerly Fengtian).
References
^鉄道車輌用ころがり軸受と台車の戦前･戦後史 (History of Roller Bearings and Trucks for Rolling Stock; in Japanese; p. 110)
July 03, 2023
china, railways, 解放4, mantetsu, mikashi, class, ミカシ, builder, photo, ミカシ1661, built, kisha, seizō, 1935type, originpower, typesteambuilderkawasaki, kisha, seizō, build, date1935total, produced15specificationsconfiguration, whyte2, 2gauge1, standard, gaugedrive. China Railways JF4 解放4 Mantetsu Mikashi class ミカシ Builder s photo of ミカシ1661 built by Kisha Seizō in 1935Type and originPower typeSteamBuilderKawasaki 11 Kisha Seizō 4 Build date1935Total produced15SpecificationsConfiguration Whyte2 8 2Gauge1 435 mm 4 ft 8 1 2 in standard gaugeDriver dia 1 500 mm 59 06 in Axle load23 00 t 22 64 long tons 25 35 short tons Adhesive weight91 72 t 90 27 long tons 101 10 short tons Loco weight124 64 t 122 67 long tons 137 39 short tons Tender weight75 76 t 74 56 long tons 83 51 short tons Fuel typeCoalFirebox Firegrate area6 25 m2 67 3 sq ft Boiler pressure17 0 kgf cm2 242 psi 1 670 kPa SuperheaterSchmidt type ECylinders2Cylinder size630 mm 760 mm 24 80 in 29 92 in CareerOperatorsSouth Manchuria RailwayChina RailwayClassSMR ミカシCR ㄇㄎ肆 1951 1959 CR 解放4 1959 end Number in class17NumbersSMR 1650 1664 1935 1938 SMR ミカシ1 15 1938 1945 CR 2701 2715The China Railways JF4 解放4 Jiefang liberation class steam locomotive was a class of superheated 2 8 2 steam locomotives for goods trains operated by the China Railway They were originally built for the South Manchuria Railway Mantetsu in Japan in 1935 History EditAfter a number of incidents involving broken crankshafts in the Mikani class locomotives as well as needing more motive power to meet the increase in goods traffic following the establishment of Manchukuo the Mikashi class was designed in 1933 1 and put into production in 1935 with fifteen built in Japan that year four by Kisha Seizō and eleven by Kawasaki As the three cylinder design of the Mikani class was deemed too complex the Mikashi class returned to the proven two cylinder layout In order to achieve a tractive effort equal to or greater than that of the three cylinder locomotives with a two cylinder engine it is necessary to increase the adhesive weight of the locomotive however this would make the axle load unacceptably high between 24 0 t 23 6 long tons and 25 6 t 25 2 long tons To overcome this a limited cutoff system was adopted with a maximum cutoff of 50 by balancing the rotational forces of the left and right cylinders the axle load was successfully limited to 23 0 t 22 6 long tons Boiler pressure was increased from 12 7 to 17 0 kgf cm2 181 to 242 psi 1 245 to 1 667 kPa whilst other new features included a Schmidt type E superheater a feedwater heater and a combustion chamber firebox Fuel consumption was also improved with the Mikashi class using from 10 to up to 22 6 less coal than the Mikani class The wheel diameter was also increased from 1 370 to 1 500 mm 53 94 to 59 06 in in order to increase the speed of goods trains however as this could result in wheel slippage on steeper sections due to the reduction in piston speed so the timetables of goods trains were adjusted accordingly Used primarily on heavy goods trains between Fengtian and Dalian to transport coal from the Fushun Coal Mine to port they could pull up to sixty 30 t 30 long tons 33 short tons coal hoppers Owner Class amp numbers 1935 1938 Class amp numbers 1938 1945 Builder YearMantetsu ミカシ1650 ミカシ1660 ミカシ1 ミカシ11 Kawasaki 1935Mantetsu ミカシ1661 ミカシ1664 ミカシ12 ミカシ15 Kisha Seizō 1935Postwar EditAt the end of the Pacific War the 15 Mikashi class locomotives were divided between the Dalian 13 and the Fengtian 2 depots and all were taken over by the Republic of China Railway Following the establishment of the People s Republic and the subsequent creation of the current China Railway they became class ㄇㄎ肆 MK4 in 1951 and class 解放4 JF4 jiefang liberation in 1959 and numbered 2701 2715 As during the Mantetsu times they were primarily used around Dalian and Shenyang formerly Fengtian References Edit 鉄道車輌用ころがり軸受と台車の戦前 戦後史 History of Roller Bearings and Trucks for Rolling Stock in Japanese p 110 Retrieved from https en wikipedia org w index php title China Railways JF4 amp oldid 1009640722, wikipedia, wiki, book, books, library,
