Running a fairly heavily modded game, so this may not be an issue with Spidertron Engineer.
When leaving a train, player inventory is reduced from from 220 to 130 slots.

some of the other mods in use
Sea Block pack, picker tools (most), FNEI, cargo ships
sorry if not enough info.

Thanks for the great mod.

Presumably a conflict between this mod's inventory size upgrades and another mod that changes the inventory size. Do you have a guess as to which mod it might be?

Big bags is most likely. I just went through all my mods and it's the only one I can see off the cuff that even touches inventory.

Should be fixed in v1.8.9. Unfortunately there's no way to change your inventory size bonus back to what it should be, so please use /c game.player.force.character_inventory_slots_bonus = 0 (replace 0 with whatever it should be for your save).

Let me know if you have more issues!