That's not considering stops, breaks in track along the way. Besides that would require a wholesale redesign of the entire shipping container industry as current box cars are not streamlined for high speed rail. As well as building is HSR lines from Spain to Asia. It might be a dream but neither one of us are likely to see it in our lifetimes.
Most likely this plan would stop at access to conventional rail line in Russia perhaps even contracting to upgrade Russian rail systems. Russia is third in miles of rail behind the US and PRC. But larger then both. Russian rail is also mixed with a large number of there rails being narrow or "Imperial gauge" both the PRC and US use Standard gauge. This means that a Train car from China's rails could be used in on any US track and a US train from the US could be loaded on a Chinese rail but neither can be used on all of Russian rail as the space between the rails is about a foot to close.
Also Russian rail is limited in scope. In the European part you can probably get anywhere in Russia. In the Asian part... Helicopter. Most Russian lines in Asia are southern with the occasional northern run until you hit Vladivostok. Then the lines get busy again. The vast majority of Siberia is only reached by air, and then predominantly Helicopter.
In rail transport in active countries six years is a long time. See #124 of this thread. It is not like California that now is asking for proposals to build trains to be put in operation on the high speed line between San Francisco and LA from 2028, if they get the financing arranged.
Rail transport between China and Germany has been vastly speeded up by improving the administrative activity necessaary for crossing borders, from more than a month to now fifteen days. I think it is now a train a week and likely to be increased soon. And this without increasing the running speed. I remember that in the EU international rail transport was at any rate when I last looked ( ten years ago ? ) very unimportants because trains were often held up at borders for 24 hours or more, while lorries crossed within ten hours forty years ago and they had later to wait even shorter times and now they don't wait at all.
There can be no objection to developing containers especially for rail transport as long as they still fit standard road transport methods. But streamline containers are not necessary. Some thirty (?) years ago there were proposals for "flat deck" aircraft in which the shipping containers were placed in the open on a deck at the position of the floor of an ordinary aircraft. I'm happy they were never built.
Break of track gauge is a bad idea. Spain used 1435 mm rail gauge for its high speed line while traditional Spanish and Portugese railways use 1660mm and 1000 mm.
Russian gauge is now 1520 mm, was 1524mm, so it's larger than standard gauge. In the units of the Roman Empire standard gauge is 4' 8.5", while Russian, Finnish and Irish gauge is 5'. The Russian and Finnish gauge was chosen in the nineteenth century to obstruct a Prussian invasion.
For Siberia you're not just forgetting An-2 and other aircraft but also the vastly more important water transport. In winter you run lorries on the rivers. And for a mine project you would build a dedicated railway if water transport wouldn't serve. When climate improves sufficiently and Siberia houses scores of large cities the railways will have been built.
