K, and?
Except they didn't? They didn't even try to. In 1944 they sent the Soviet a couple thousand broad gauge locomotives rather than try to entirely recreate the Soviet rail system in Siberia, plus the US+UK+USSR combined built less locomotives than Germany did during the war and focused on other things like AFVs. Regauging was the easiest issue, the hard stuff was all the other things that go with rebuilding the entire system:
https://www.hgwdavie.com/blog/2018/...y-operations-in-the-russo-german-war-19411945
And?
This commenced in October 1941, though some goods had been moved prior to this under the "cash and carry" agreement. The route was affected by the start of hostilities between Japan and the US in December 1941, but was not interrupted as Japan and the Soviet Union maintained a strict neutrality towards each other for the duration of the conflict, changing only in August 1945.
Due to this neutrality the goods could be moved only in Soviet-flagged ships, and, as they were inspected by the Japanese, could not include war materials. The route was therefore used to transport foods, raw materials and non-military goods such as lorries and other road vehicles, railway locomotives and rolling stock. It was also the most practical route for goods and materials produced in the US western states. During the conflict the Pacific Route saw a steady stream of goods moved from the west coast of the United States and overall accounted for some 50% of all Lend-lease goods to the Soviet Union. The route closed in September 1945 with the end of the conflict and the cessation of the Lend-Lease scheme.
The Pacific Route was augmented by the Alaska-Siberia Air Route (ALSIB), which was used to fly combat aircraft and airborne goods from North America to Siberia and beyond. This route was also immune from Japanese interference, as it was undertaken by Soviet pilots based in western Alaska. ALSIB was used for delivery of nearly 8,000 aircraft, air cargo and passengers from 7 October 1942 to the end of hostilities.
Pacific Route cargo to Vladivostok was transported exclusively aboard independently routed Soviet ships. Twenty-seven United States cargo ships built about 1919 were transferred to the Soviet Far Eastern State Shipping Company (FESCO) as Lend-Lease in 1942. Older Soviet ships excluded from the JW convoys of faster Liberty ships to minimize travel time through the dangerous Barents Sea were suitable for the Pacific route, and were later augmented by Liberty ships supplied to the Soviet Union.
The operations of the Pacific Route were organized by Leonid Belakhov, Deputy Commissar and Chief Political Officer of the Soviet Merchant Fleet (MorFlot). Goods were moved from US west coast ports (principally Los Angeles, San Francisco, Seattle, and Columbia River ports) and moved via the Great circle route across the Pacific, skirting the Aleutians and the Kuriles. From there they passed via the Perouse strait to Vladivostok. When the Perouse strait was frozen, Soviet ships traveled south of Kyushu and entered the Sea of Japan through the Tsushima Strait to reach Vladivostok. Cargoes including military goods avoided Japanese inspection during the summer months by partially unloading in Petropavlovsk-Kamchatsky to reduce their draught to cross the shallow Amur River estuary and enter the Sea of Japan via the Strait of Tartary. The total distance was 6,000 miles and took 18–20 days From Vladivostok nearly 400,000 railway car loads of goods were transhipped via the Trans-Siberian Railway to the industrial heart of the Soviet Union, a further 5,000 miles.
A branch of the Pacific Route began carrying goods through the Bering Strait to the Soviet Arctic coast in June, 1942. From July through September convoys of shallow draught ships and icebreakers assembled in Providence Bay, Siberia to sail north through the Bering Strait and west along the Northern Sea Route. Total westbound tonnage through the Bering Strait was 452,393 in comparison to 8,243,397 tons through Vladivostok. Part of this northern tonnage was fuel for the Alaska-Siberia Air Route airfields described below. Provisions for the airfields were transferred to river vessels and barges on the estuaries of large Siberian rivers.
http://english.ruvr.ru/2007/12/19/168522.html
http://columbia.washingtonhistory.org/m ... 06-a2.aspx
http://www.kscnet.ru/ivs/bibl/paperno/for_65_engl.htm
Part of that effort was the ALCAN Highway and it was also the reason for the hard fought Aleutians Campaign. The Japanese made a big mistake when they did not make a stronger stand there. A lot of what massacred them in Manchuria was shipped from Seattle and Portland and went that way.