Long distance cargo payments

[minormenace]

I'm playing on a custom scenario that's 4096x2048 with a FIRS variant and I've been moving coal long distances and after doing some testing I noticed that if I take it 200 blocks vs 2000 blocks the payment is basically the same, and so my trains are costing far more in maintenance and the long distances are basically pointless.

Can anyone advise as to what I'm doing wrong, or if the cargo payments just aren't designed for this?

[odisseus]

The amount paid per unit of cargo is a function of time and distance, but this function is highly nonlinear. (Here's a 3D plot for oil, where X is distance in tiles and Y is time in days; the plot for coal should look roughly the same.)

The Wiki has some interesting charts which show the relationship between distance, speed and income. The most notable is the one that shows the income for passengers (a cargo with high decay rate) as a function of distance, given a fixed speed of 100 km/h.

Distance vs income.png (3.06 KiB) Viewed 725 times

The exact shape of the plot depends on the cargo decay parameters and the speed of transportation, but the important features are present in all cases: a parabola-shaped hump, followed by an upward-sloped straight line. This means that there's an optimal delivery distance, after which the payment amount begins to drop. However, after some point the payment amount begins to grow again; this growth continues linearly without limit.

This calculation doesn't take into account the maintenance costs of the vehicle, which are negligible under the default settings. With custom add-ons, exploiting the extremely long routes may or may not be feasible.

[2TallTyler]

That Wiki page will need updating, since OpenTTD 14.0 will include this change to the formula (check the link for lots of new graphs including a link to an interactive tool).