"weight" in vehicle entity prototype: what unit is it in?

[slippycheeze]

I can't figure out what unit the "weight" value in the vehicle entity is in, or if it is just a magic number that plugs into a formula I have not yet found to calculate the behaviour of the vehicle.

Part of my problem is the defaults: car is 700 units, locomotive is 8,500, and the tank a massive 30,000.

Given those there isn't any real match to real world units that makes sense if all three are the same physical unit. Kilograms was my best guess, but for them the car is about half the weight I'd expect, tank is light but not unreasonable but ~ 3/4 to 3/5ths of what I'd expect (40-55 metric tons), and the locomotive is wildly light compared to the real world, where it'd be more in the region of 150,000 to 200,000 kg.

Even assuming the locomotive uses some different unit for weight, both entities are much lighter than I'd expect. So...

What unit of measure is this in? If the answer is "arbitrary", is there any information that could be shared on the math it fits into?

Alternately, pointers to where in the wiki (or forums) this is documented, and I couldn't find, appreciated. :{)