February 1956 at the 20th Communist Party Congress it was decided that steam locomotive construction in the Soviet Union would be curtailed and that steam power would be replaced by electric and diesel-electric locomotives. The last steam locomotive produced at Kolomna, P36-0251, was outshopped on June 29 of that year. On the smoke box door was written "1869 - 10420 - 1956 Last steam locomotive built by Kolomna Works" (10420 being the serial number of the locomotive). Specifications The P36 chassis consists of a main frame and two bogies, a leading bogie and trailing bogie. The frame consists of 140 mm thick bars, similar to class L and class LV locomotives. All axles are equipped with roller bearings and the drivers employ disc wheels. The drivers are 1850 mm in diameter, the same as used on Su and IS class locomotives. The all-welded boiler includes 66 flues and 50 fire tubes, with the design of the boiler and superheater identical to that used in the experimental P34 type locomotive. On the prototype locomotive a smoke box blower was employed, but was omitted from later locomotives due to reliability problems. On the first prototype locomotive a six-axle P35-type tender was used, but on later locomotives a six-axle P58-type tender was employed instead. An automatic stoker is fitted to the locomotive. Two turbogenerators (duty and standby) supply 1 kW of electricity to the train. Operation In regular service P36 type locomotives were generally used on mainline long-distance trains. In particular the P36 locomotives were used on the Moscow-Skuratovo, Moscow-Michurinsk, Moscow-Pokhvistnevo, Moscow-Leningrad, Moscow-Murom, Krasnoyarsk-Taishet and Krasnoyarsk-Ilansky lines in the Russian SFSR. Use of this type made it possible to increase not only the weight of the trains used on these lines but also their speed. For example, when P36 locomotives were placed into Moscow-Leningrad service they reduced running time by 1 hour 45 minutes to 9½ hours with average speed increased from 58 to 69 km/h. Mass conversion of main line railways to diesel and electric power led to P36 locomotives increasingly being relegated to more remote and less used lines; by 1958 the locomotives had already been replaced on the Moscow-Leningrad run. The last year when P36 locomotives were used in active service was 1974, running from Mogocha and Bilohirsk depots on the Trans-Baikal Railway, though in 1976 there were still 247 P36 type locomotives listed as available on the railway inventory.