Getting supply out of depots in home countries

[Sertorius21]

Playing the German in December 1941, I face supply issues which is not a surprise in itself, but what puzzles me more is the following combination:

- a lot of supply in Germany, Hungary, etc. including in a handful of level 1 depots that have (many) thousands of tons sitting idle. Of course this is outside of national supply centres that are overflowing.
- the rail lines are all in green or yellow status, yellow usually with units being transported
- All rail marshalling yards have been repaired and linked except a level 2 one.
- Of course the depots are a few level 4 near the front, some level 3 behind or where it is less critical, then level 2s. Usually there have been HQs for a while on level 4 depots.
- All this has been ongoing for a while, not just since mud and blizzard. Yet this becomes a real issue with the blizzard.

Clearly I must have missed something, help (if there is anything that can be done) would be highly welcome before I conclude the next turn.