ALCo RSD-1, 127-ton, 1000hp, Diesel Road Switcher When the Iran was occupied in August 1941 by British and Soviet forces in order to open a save "back-door" for Lend-Lease deliveries to Russia, it happened not to the least in regard of the Iranian State Railway. The »ISR«, as called briefly, had been built in the late 1930s primarily to connect the Persian Gulf port of Bander-Shahpur with Tehran and the Caspian Sea port Bander-Shah. There also existed a section leading northwest to the Iranian-Russian border, but this part was not yet fully completed. After the successful occupation, the British and Soviet forces immediately took over the control of the Railway and launched a regular transport of all sorts of supply goods. However, they soon found out that the existing British steam locomotives of type Stanier 8F 2-8-0 and others were unable too tow sufficient amounts over the rough Iranian mountains and through the unventilated tunnels. At this point, in late 1942, it was decided that the U.S. Military Railway Service (»MRS«) as part of the USA Transportation Corps (»USATC«) take over the Iranian Railway by 1943 in order to increase the flow of supplies so urgently needed by the Russian allies. To overcome the existing problems, 57 of the 150 new ALCo RSD-1 Diesel Road Switchers were imported and erected until May of 1943. 70 others were directly sent to Russia as part of Lend-Lease, of which 58 actually arrived and 12 were lost en route. Often deployed as pairs in order to provide maximum power, the Iranian Alcos soon became famous as the locos of the 1000-ton »Aid-to-Russia« trains. Note: The Iranian Railway hauled no less than 7 times as much supplies through the Persian Corridor to Russia as did the Studebaker US6 w/Semitrailer equipped Motor Transport.

On July 28, 1944, the delivery of the one-and-a-half millionth ton1 to the Russians called for a celebration. A 48-car train, loaded with M4A2 Sherman tanks and headed by an Alco Diesel, stopped for flourishes at all the main stations along the northbound route and was the center of culminating ceremonies at Tehran on that date. Fanfare, speeches, and a souvenir pamphlet took their due places in history and, as the American soldier railroaders handed over the trainload of tanks and war materiel to their Soviet opposites, one of them gave a cigarette to the burly Russian girl who was fireman on the northbound engine. Cameras clicked, and there were cheers. (Source : Vail Motter) 1According to other sources, the three millionth ton of delivery was celebrated.

Note:
In Iran, the heat was so intense, that the Alco diesels, like the »8005« shown here, operated with the engine access doors removed.