Lol, Douglas has made a Tutorial and is struggling with the game. Lol !!!
Maybe you should read my Tutorials [Advanced] Train Fever + CargoMod Part 1 and 2 in total 140 pages.
Frequency for Resources has to be less than 9 Minutes, Frequency for Goods has to be less than 5 Minutes (based on City demand). Walking-time is included.
You can calculate distance divided by earnings to amount of Cargo. Modifier for Persons to transport are 1 and the modifier for Cargo is 2.