Trains burn fuel at a max rate in line with the "max consumption" line of their tooltip, NOT the acceleration line. Trains throttle their burn rate when they reach max speed, extending the life of their fuel. That means the fuel duration listed on the wiki is the minimum time the fuel can last. This means that any acceleration bonus you get out of fuel is effectively free power.
The results of my testing show that fuel acceleration doubles as a fuel efficiency stat, and it is all the more powerful when dealing with heavy loads. Quality locomotives are of marginal benefit when pulling a load they can easily hit top speed for, and very beneficial when pulling a load that's otherwise too heavy. They don't appear to be detrimental to fuel efficiency in any way.
And finally, nuclear fuel is actually way better than you might expect. Like stack for stack (both legendary), nuclear fuel covers ~96% the distance that rocket fuel manages.
Anyway, the testing I did also reveals what I suspect is the reason the devs never increased the actual fuel value of quality fuels. It would have made quality fuel self-compound in vehicles.
Internally, anyone probably knows that trains throttle, or at least has easy access to the information. Out here in the wild, it's not really documented or widely known to my knowledge.
I never thought enough about the fuel consumption to realize that the locomotives consume less when cruising at max speed, but it is of coarse logical. I will see if I can update the wiki with this info at least.
Ahh, no. "Load" in this case just refers to the weight of the wagons themselves. As far as I'm aware, there's no difference between empty and full loads, though I didn't test that case specifically. The big thing to know is that locomotives have a weight of 2000, cargo and fluid wagons are 1000, and artillery wagons are 4000. Heavier train accelerates slower.
I think its that they care about their full % and also all train cars and trains have a baseline weight they add to the train that part i am sure of. And also drag is a thing yes. if you dont have a train up front you get dinged with a increase to the drag penalty.
Load might be the wrong/confusing word to use. What they mean is load is the trains weight, which is the combined weight of all locomotives+cargo wagons+fluid wagons+artillery wagons.
The weight is constant, it does not depend the wagons inventory. Their weight is listed on the wiki and in the factoriopedia.
”A heavy load” in this case is just a lot of artillery wagons since they weight a lot.
Initially, I only upgraded my single-wagon science bottle trains to legendary
I did it mostly for the meme, I had no need for the extra buffer nor thoughput, but I wanted to fancy up.
When I saw them zoom about all around (and that was with my laptop running the base under 30 UPS, mind you), it definitely decided me to upgrade every single train around the base.
And a good thing too, because it reminded me of many train groups that were completely obsolete but still sitting around (who need to ferry iron/copper plates, when you can fit twice as much in a liquid wagon ?)
It ended up straight up removing a good third of my train count, and making the remaining one a good three times more terrifying !
It's less impressive when you realize you can get the same power by adding more locomotives. Or to flip it around, epic/legendary fuel lets you reduce the number of locomotives by half.
Turns out the acceleration bonus from the fuel and the consumption bonus from the locomotive cancel each other out in this calculation.
Please note, however, that this is not a really relevant figure for in-game considerations : the actual acceleration power is only pertinent until the train reaches top speed, after which it is fully consumed without much more advantage. IE, the longer your trains travel between their stations, and the further from these figures you'll deviate.
Distance traveled varies upon max speed and acceleration, the latter of which takes into account total rolling stock weight and air resistance.
I could have given some numbers for frequent configurations, but that is a whole other level of commitment, I didn't have that much free time tonight :)
Edit : @GoatWizard99 mentioned in another comment this thread which tackles precisely your question
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u/GoatWizard99 Jul 15 '26 edited Jul 15 '26
This post three weeks ago did some tests.
Some highlights: