the connection from another side is how this game works. If you want to connect engine to the carts from other site you have to disconnect every cart then go around and connect it again. Every time you connect cart, the game determines where is front and where is back (rear end) and there is no feature in this game to pull something from it`s "rear end".
To load diesel/water/herb you need to press U to select which tank you want to use. Below you can see the trigger boxes. The place where you want to load/unload have to be in corresponding trigger (it`s invisible in the game). Left - water, center - herb, right - diesel.
