It has been said often, and multiple times even by some dev (boskid was the last one as far as I remember) that the regular solution is to provide enough items in the first place. So the solution for the problem you mentioned is: "increase ore output", which means: "build more mining...

Obviously this won't work for all cases, though there may be tweaks and modifications here and there that could be made to handle some of them. Yeah that would work too - i solved it with signals that were sent to the train inside the drop off stations. where ever less iron ore is the trains leaves...

hi, i am still missing the opportunity to split the output from a train station evenly to all trains that want to go to that station. for example: i've one pickup station for iron ore but if i have two trains that will pick up that ore and the production of the ore is too slow to fully support both ...