Hi,
is there any known formula to calculate the topspeed and acceleration of trains?
Google didnt help much for long trains I´ll probably need more than 2-6-2
Train acceleration and speed
-
- Fast Inserter
- Posts: 117
- Joined: Wed Apr 06, 2016 4:01 am
- Contact:
Re: Train acceleration and speed
empiric data for train speed:
https://www.reddit.com/r/factorio/comme ... comotives/
https://www.reddit.com/r/factorio/comme ... xperiment/
The formulas used for acceleration and top speed are not realistic.
Acceleration seems to be mostly a function of max_power and total weight ignoring friction_force and weight of the locomotive.
A train with 100ton can be accelerated by a mere 1ton locomotive if you give it enough max_power which is nonsense as it's wheels would only spin.
Top Speed has a hard limit with max_speed and a calculated limit derived of total weight, total max_power and total air_resistance. air_resistance seems to factor in more at higher speeds which is at least somewhat realistic.
https://www.reddit.com/r/factorio/comme ... comotives/
https://www.reddit.com/r/factorio/comme ... xperiment/
The formulas used for acceleration and top speed are not realistic.
Acceleration seems to be mostly a function of max_power and total weight ignoring friction_force and weight of the locomotive.
A train with 100ton can be accelerated by a mere 1ton locomotive if you give it enough max_power which is nonsense as it's wheels would only spin.
Top Speed has a hard limit with max_speed and a calculated limit derived of total weight, total max_power and total air_resistance. air_resistance seems to factor in more at higher speeds which is at least somewhat realistic.
My Mods: mods.factorio.com
-
- Fast Inserter
- Posts: 117
- Joined: Wed Apr 06, 2016 4:01 am
- Contact:
Re: Train acceleration and speed
Thanks I know those tests, but it doesnt help me, how much cargo wagons a 3-x-3 can handle I hoped, the devs did post something or anyone who knows how checked it in the gamefiles
Re: Train acceleration and speed
What do you mean by "can handle"? accelerate to max speed? If so in what time?terror_gnom wrote:Thanks I know those tests, but it doesnt help me, how much cargo wagons a 3-x-3 can handle I hoped, the devs did post something or anyone who knows how checked it in the gamefiles
As far as I know the devs never published the train fomula. Here's a really nice one proving L-C is not equal to LL-CC in terms of acceleration
Edit: After doing some testing with 0.14.21 myself I think the formulas have changed since those test I linked. They seem more realistic now.
L-CC accelerates faster than CC-L, used to be the opposite
L-C-L accelerates faster than L-backwards L - C
My Mods: mods.factorio.com
-
- Fast Inserter
- Posts: 117
- Joined: Wed Apr 06, 2016 4:01 am
- Contact:
Re: Train acceleration and speed
Thank you, so I´ll do some tests of my own. I just hoped, there are some (known) formulas to to see how the numbers changes and finding a "sweet spot"
Re: Train acceleration and speed
I'm still using L-CC trains because the last time i looked into this topic, the answer was:
1 locomotive by itself = highest accell and top speed.
1 loc per 2 cars (or reverced loc) second best.
I dont remember exactly where or what i read back then, but my impression was that a LL-CCCC train would be as fast as an L-CC train, and same as LL-CC-LL (where the other LLs face wrong way and are dead weight).
so for same speed i would assume that if you want bidirectional trains, it would be LLL-CCC-LLL to match the speed of L-CC trains.
If you dump more cars between the two sets of locos then there are locomotives on each side then the train will have less then a 1/2 ratio of "working locos"/pulled weight and be slower then a LCC
This was the main reason i decided that LCC with roll on roll off turning around would be way and i've built all my train systems that way since. If i ever make a real large base, and need insane amounts of trains coming in from far away, then i'll probably go to a LLCCCC system for far away outposts and have a transfer system betweeen the long distance 2-4 trains and the short range 1-2 trans
1 locomotive by itself = highest accell and top speed.
1 loc per 2 cars (or reverced loc) second best.
I dont remember exactly where or what i read back then, but my impression was that a LL-CCCC train would be as fast as an L-CC train, and same as LL-CC-LL (where the other LLs face wrong way and are dead weight).
so for same speed i would assume that if you want bidirectional trains, it would be LLL-CCC-LLL to match the speed of L-CC trains.
If you dump more cars between the two sets of locos then there are locomotives on each side then the train will have less then a 1/2 ratio of "working locos"/pulled weight and be slower then a LCC
This was the main reason i decided that LCC with roll on roll off turning around would be way and i've built all my train systems that way since. If i ever make a real large base, and need insane amounts of trains coming in from far away, then i'll probably go to a LLCCCC system for far away outposts and have a transfer system betweeen the long distance 2-4 trains and the short range 1-2 trans
Re: Train acceleration and speed
I was under the same impression that 2L-4C = L-2C in acceleration and top speed, but that's not true (anymore).RoddyVR wrote:I'm still using L-CC trains because the last time i looked into this topic, the answer was:
1 locomotive by itself = highest accell and top speed.
1 loc per 2 cars (or reverced loc) second best.
I dont remember exactly where or what i read back then, but my impression was that a LL-CCCC train would be as fast as an L-CC train, and same as LL-CC-LL (where the other LLs face wrong way and are dead weight).
so for same speed i would assume that if you want bidirectional trains, it would be LLL-CCC-LLL to match the speed of L-CC trains.
If you dump more cars between the two sets of locos then there are locomotives on each side then the train will have less then a 1/2 ratio of "working locos"/pulled weight and be slower then a LCC
This was the main reason i decided that LCC with roll on roll off turning around would be way and i've built all my train systems that way since. If i ever make a real large base, and need insane amounts of trains coming in from far away, then i'll probably go to a LLCCCC system for far away outposts and have a transfer system betweeen the long distance 2-4 trains and the short range 1-2 trans
When testing locomotive parameters for this thread i built a very basic test track. Here's the results:
L-2C vs 2L-4C
My Mods: mods.factorio.com
Re: Train acceleration and speed
Well, that actually makes sense, because both trains should experience roughly the same amount of air pressure, and that will affect the single locomotive more.Optera wrote:snip