Improved the common 1.1 Train Limit Loading Design

[JayS]

I suppose many people have already seen the use of the circuit network to dynamically set the 1.1 train limits at loading stations so that a train will only arrive if there are enough items for it to load completely. I.E. if you have an ore patch and 1-4 trains, you divide the buffer at the loading zone by 8k to get the number of trains that can load, then max that with how many trains can wait at that station.

The problem with this setup is that it under-reports the number of trains that can fill in some situations. Say you have a station with 16k ore in the chests, and waiting room for 2 trains. Once 1 train starts loading there, the train limit will decrease to 1 and even though there is enough ore for 1 more train, another won't be dispatched until the loading train leaves. This is a bigger issue if you play with ore patches very far apart, because now a train has wasted a significant amount of time sitting in a depot when it could've been traveling to the ore patch. See this thread for more discussion of this issue - viewtopic.php?f=18&t=96263

The solution I have come up with is to feed the train contents back into the division, so that instead of just being the buffer chests divided by 8k, it is the buffer chests + train contents.

See this blueprint for the improved circuit - https://pastebin.com/jPgDa1nq

You need to adjust the decider combinator condition to leave enough room for the capacity of your inserters that load into the train, and the division combinator to be based on your number of cargo wagons.