Is it possible to add support for adding custom stuff on the workcarts from config like creating 8-10 placeholder positions? You can stick whatever you want then and when workcart is spawned you gonna have the stuff on it. Ex.  add storage box or small furnace or recycler or in my case stationary scientists or locked crate or lootable crate prefab or whatever else?

Allowing custom attachments via config would be fairly straight forward to implement. The main issue is that different types of entities need different treatment, so the plugin would have to be developed ahead of type to make certain kinds of entities compatible, such as deployables, electronics, NPCs, etc.

Some questions to help me understand how you are using the plugin and how you would use this feature.

1. Are you currently or planning to automate all workcarts, or do you intend to allow some to be player driven?
2. If you were to only automate a subset of all workcarts, would you only want the attachments on the automated ones, or on all workcarts?
3. Would you want attachments to vary to vary by some degree of randomization between workcarts? Like a % chance that each attachment spawns? Alternatively, would you want to use custom trigger profiles, so that workcarts automated at different locations could get different attachments?
4. Specifically what kinds of entities would you expect to be able to spawn? For example, scientists, storage containera, cctv cameras.
5. If you were to add storage containers, would you want them to be saved and persisted across reloads so that player items are not lost? As it stands, I'm not sure how useful a storage would be, since the player would likely not have enough time to make the trips to offload the storage before the workcart leaves again, unless there were additional functionality to offload them to a container at a train station or other stop.
6. If you were to add scientists to the workcart, would you expect them to be hostile to players, and/or to other NPCs like tunnel dwellers? If you expect them to be killable, would you expect them to respawn after some time when no players are nearby?
7. If you were to add loot crates, would you expect them to function like other loot crates, meaning similar loot table and respawn rate? Which loot plugins would you expect to have compatibility with? Would you also expect to be able to configure their loot profile in this plugin's config?

Uh, Thanks for the reply and I guess will send here the original initiator to type in this thread as soon as possible and reply to your questions. I am currently helping one guy and he's trying to do something. As I understood from him he loves this plugin because 

1. "That new plugin I got the driver and train is invincible" - he said this for your plugin (this one) which is great for his use as I know.
2. He can spawn these trains above ground or whatever he does more.

And as far as I know, he's using another paid plugin that runs CargoTainEvent with npc's and locked crate but something is not ok and he's loving this from uMod for some reasons and he will tell more when replying here. The paid plugin has a lot of Hooks/Api's for plugin developers but I do not understand a lot about this stuff so yeah but probably something can be used, idk. He's trying to combine both or just use the good part from both plugins in one - the "driver and train is invincible" from this one idk... He mentioned early to me about something like CH47 in the whole scenario too so I guess it's better when he replies here and explains.