But even with a 75 or 80 day lag to the delivery as reported by the time table (and it was a single train running on this loop). The game's definition of "3 months" just didn't seem to match my intuitive definition of 90 days.
It might be using calendar months. I started reading my code to establish the facts, but I got bored and don't have my glasses on
Supplies were originally added to try and 'encourage' (i.e. force / incentivise) the use of road vehicles, small ships and helicopters. Forcing players to do anything in OpenTTD tends to be a flawed concept though
Over time supplies have evolved a bit, their main facets now are:
* they do encourage one-to-many distribution networks (but noting that cargodist does not work well this)
* steady flow of 30t-90t amounts will keep production reliably high
Supplies also have a really interesting failure case. Sometimes a dense network can be built, where the output from primaries loops back as supplies for those primaries. This often involves a very high volume of trains etc, and can work great as long as nothing goes wrong (like a train that gets lost and blocks a key junction).
If such a dense network does block for anything, supply deliveries drop, then primary production drops off a cliff, and flow rapidly stops for the *entire* network, with trains backed up on all the mainlines and branches. It's very rapid cascading failure, and is quite interesting to see. It can be avoided by different train network design, and/or by making sure the linkgraph for a specific supplies network is always a DAG
I digress probably