First of all I noted, that all "dual tracks" which are coloured yellow seem to have the exact same rail usage of 5416 in the whole controlled area. That's why I started some testing.
Setup:
- Grand Campaign
- Human vs Human
- Warsaw depot = 4
- set all other depots to 0
- removed all air commands (added some to warsaw area later on)
- moved units in the direction of Warsaw
- placed 4th Army in Warsaw (increasing capacity from 50k to 60k)
- placed FBD in Warsaw (to increase "pull effect")
What I encountered:
In screenshot 1 you can see that Warsaw is the only Depot which isn't set to "0" and I activated the "freight flow" option using the "8" key. In screenshot 2 you can see the rail network around Warsaw with rail usage of neighboring Hexes. I edited the picture to show results of several screenshots. I'd like to know how Warsaw is able to get 58913 Freight from Prague using this rails, since the sum of all neighboring rails is ~14,5k.
In screenshot 3 you can see the Freight data (maybe this helps with analysing/explaining)
To sum up:
1.Why do all yellow double tracked rails show the same usage of 5416?
2.How can a Depot get ~60k with surrounding rails only showing a usage of ~15k?
I'd rly appreciate if some veteran of this game series could enlight me, since I am more than just confused at the moment.



