Saturday, November 25, 2023

Bolivian metre-gauge mountain diesel locomotive


A publicity shot of the Sulzer powered locomotive destined for the Machacamarca - Uncia line in Bolivia. The upper plate in the center of the locomotive reads PM&EC, FCMU, #20, the plate underneath provided details of the builders of this locomotive (Sulzer, Oerlikon & Les Ateliers Metallurgiques SA). The livery seems to indicate two colours for the body side, but the colour pictures eleswhere in this article show a solid colour for the locomotive body. Additionally the frame appears to carry the same colour as the lower body, but in the colour views elsewhere the frame and buffer beam are painted bright red.

About 1939 the Patino organisation placed an order with Sulzer Brothers for a diesel electric locomotive suitable for hauling passenger or freight trains. The order was in many ways unusual. Not least was the terrain the locomotive was to work in, high up on the Bolivian 'Altiplano'. The Patino organisation operated the railway between Machacamarca & Uncia, which served the silver & tin mining centre around Uncia, Huanuni & Catavi. This 63 mile [101 km] long metre gauge line which included the three mile Catavi branch varied in altitude from 12,200 feet [3719 metres] to 14,400 feet[4,389 metres] , included a maximum grade of 1 in 40 [2.5%], although the ruling grade was slightly easier at 1 in 58 to 1 in 63.

The line had begun dieselisation early, in 1933 (?) two diesel electric railcars were obtained from Linke-Hofmann-Busch, Germany, powered by a six cylinder Linke-Hofmann Busch diesel engine. These railcars would operate with non-powered passenger coaches to provide more passenger capacity. At least Motor No.2 (with LHB builders plate dated 1931) survived to find a place in the railway museum at Machacamarca.

Sulzer provided for these conditions with a locomotive 50'6" in length and 9'1" wide, with two cabs and full width body riding on two three axle bogies. Power came from a Sulzer 6LDA28 engine. The engine was normally rated at 815bhp at 700rpm continuously (915 bhp at 750rpm at the one hour rating). However, due to the exceptional conditions on the Bolivian line the continuous rating was 650bhp at 700rpm (730bhp at 750rpm for the one hour rating). The engine was pressure charged on the exhaust gas system using a Sulzer turbo blower set using plain bearings for the shaft. Dry weight of the engine & blower group including the welded steel underbed was 8,450 kg.

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