Using the plugin in some way may cause server or client lag. This page details causes of lag, and how to deal with them.
Complex 3D models
Minecraft is not very good at rendering complicated voxel models. If you use a custom resource pack on the server that has far too complicated models, it can cause the FPS of the client to drop. Always review models before you use them on a live server. The model JSON filesize is a strong indicator.
When configuring the physical attributes of a cart in the attachment editor, the cart size can be set very large. This changes the bounding box of the entity itself, which may result in worsened TPS on the server. The main cause is the block collision calculations the server does. To prevent this problem, disable block collisions entirely
|Command:||/train collision block cancel|
Large wait distance
The wait distance property can be set for a train, so that it will keep distance to trains up ahead. This does require tracking all the rails the full distance in front of the train. Setting this distance too high can therefore result in worsened TPS on the server.
Keep chunks loaded
Trains can keep chunks loaded, but too many loaded chunks may also hurt server performance. They consume RAM, which might cause an out-of-memory situation. They may also contain entities or redstone contraptions that all contribute to a worsened TPS. As trains move, they load and unload chunks continuously, which might also cause problems.
Generally a single train keeping chunks loaded is not a big deal, it's no different from a player moving from one location to another. But having hundreds of them on far reaches of the server could cause problems.