@Xaerthus, thanks for additional info, if it is most simple way to make game more stable with just increasing mass, because of game engine limitations, leave it like that.

That axle on picture was fairly small, part of more complex mechanism. I have added it between more for aestetic reasons and I was catched by surprise why previously well balanced mechanism stopped working as expected by all sudden.

I was aware that additional mass might cause slowdowns, but I didn't expected that just one small block can cause such difference. I didn't encountered issues with pulleys connected with steam engines, but if they were part of controling system, that is something to be aware of and put in consideration in future builds.

Anyhow, thanks for info and taking time to look into it.

@kcs123
The rpm loss is not caused by the pulley mass, or at least not directly. The reason it happens is because of how the physics engine of the game calculates grid inertia. Basically it takes the largest value from width, length and depth and treats the sub grid as a sphere of that size and the mass of the blocks combined. This simplification results in significantly more resistance to turning with mass increase, than it would be expected from real life experiences.

Now, the pulleys need to have such mass to add stabilisation to engine shafts when they are mounted onto them. Adding mass to grids connected through constraints, does strengthen those constraints.

How to get rid of that issue though?
1. Use the shafts that come together with the wooden pulleys and refrain from making long axles.
2. Few wise people have made a fix that causes the grids to be calculated correctly. Though mind that it is applied through manually swapping files in the game directory and you won't be able to join most public servers (other than the PNL server it was made for). For more info, please join the PNL discord server:
https://discord.gg/YuJwhHS

I like those pulley models because it allows direct attachment on catch block without need of extra 1 small block size between catch block and the rest of mechanism.

But, aren't those train pulleys a bit too heavy ? With like this and nothing connected elsewhere:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2335791763

RPM is halfed in comparison with this setup with only one train pulley:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2335795012

It was take some time until I figured out that difference in weight cause such large performance loss. Then I checked weigth of train pulley: 75 kg. While vanilla pulley size 1 weight is 5 kg.

I understand that there must be gamebalancing reasons somewhere between train and vanilla pulley, but shouldn't 15 kg vs 5kg be enough, instead of 75 kg ?