Factorio Forums

I use this formula so my trains won't run half-full:

threshold = avg [cargo or fluid wagons count] * [40 (Cargo stacks) * stack size or 25000 for fluids].

Is it possible to implement it into mod as an option for default threshold when only one item is requested? Of course there should be a setting to specify how many locomotives are expected per train so that they are not counted as cargo wagons.

What numbers should it use when there are multiple train lengths and/or wagon capacities?

I think that by default it's ok to assume that a player uses only vanilla wagons which have the same capacity unless you lock their slots.
When a station declares that it accepts trains from 2 to 4 cargo wagons (or with locomotives min=3, max=5) I would use average count 3. As I understand this doesn't limit trains with less capacity to come in but requesting shouldn't start before the threshold.

btw I use only fixed-length trains for requester stations (min=max) because otherwise less longer trains would have to wait for overfilled forward chests.

Fixed numbers are more robust.
It's only a fallback for the really lazy anyway. Thresholds should always be set manually to fully utilize LTN.