Factorio Forums

I just started with LTN. I managed to get things working correctly after finding this excellent tutorial by Tuplex (https://www.youtube.com/watch?v=a3ujEdPfGHk).

One concern that I have is "what happens" if demand on the requester end is such that the train fails to unload some of the wagons and items are left on the train? Does it not pollute the next delivery? How do we compensate for this issue?

Yes, that would pollute follow-up deliveries. Best practice is to never request more items than the requester's buffer can store. It is still a good idea to have a backup plan when things go wrong. For solutions, have a look at the LTN subforum. Especially at the design thread and the depot blueprint Optera posted. You can also try LTN Tracker, which provides a GUI and alerts when trains come back to a depot with leftover cargo.