Yeah, my memory is not what it once was
The Germans couldn't use their Trains or rolling stock because the Russian railway tracks were a totally different guage. It would have cost billions, taken too long to convert, and used too many resources. Plus the Russians used their "scroched earth" policy and left absolutely NO trains or rolling stock intact.
A very effective policy.
As for the "transportation of Jews" thing, well, that subject opens a whole other can of worms.
I have PMd the people who requested the doco, if you want it please ask, I don't feel too easy offering a link on an open channel
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