Hi, I think there should be an option to disable default chunkloading for cars spawned among with village because they keep loaded a lot of unuseful chunks especially on very large maps and they make chunkloading impossible to work for new trains created by players.
In few words, it would be useful if the mod load only chunks around trains chosen by player or player owned/created ones.

I'll take a look into adding that as a default feature in 019, however it will only apply for newly spawned ones, after the initial spawn there's no reliable way to tell if it's still in a village or if a player took it and is using it.

For the ones that are already spawned, there's a "Chunk Loader Activator" tool you can use to manually disable their ability to chunkload.
Additionally there's a ForgeChunkLoading.cfg file in the server's config folder, which you can use to increase the max number of entities that can load chunks by increasing I:maximumTicketCount under the default section.
Naturally the more chunks loaded the harder it is for the server so keep that in mind, especially on the usual server hardware, minecraft isn't built to work with xeon processors (there's no "proper" threading system to make use of more than 3 cores).