Supply: Move unit by rail vs. normal movement

[AbeMuc]

Dear Wargamers,

I am in the middle of an ongoing Lets Play-Series streaming Sundays and quite an important question came up.

It is about using rail transfer or normal movment for units behind the front. For example I have 4 infantry divisions near Warsaw and want them to move up to AGN. I am in no hurry to get them there. But I have no clue which way of transport is better supply-wise.
Is moving them by train limiting supply arriving at the front?
Or are they draining more supplies by moving them normally as they use supply/fuels to get there in 2-3 moves insteas of one move by train?

Just to share you some insights into the project: Start of Turn 5

[Karri]

Rail movement uses rail capacity, which will definitely hurt more than just marching there. Especially early in the game, as you are most likely relying on a single rail line, that would definitely take the railroads to max capacity. You can see the rail usage/depots by pressing 'n'. Moving more than one division is sure to turn the rail red.