siege equipment

[Didz]

EDIT : OK, I was : your point WAS that they weren't use in field battles

Also...by implication the seige engineer unit would only use up one army slot, if that, (he could for instance be an agent, and just attached to the army) but be able to manufacture/assemble multiple seige engines and weapons.

Its actually quite ahistoric for armies to cart around their seige train when on campaign. Usually it was only called forward when a seige was being conducted. Wellington for example kept his seige guns stored on ships in the Tagus until he needed them, rather than drag them up and down spanish goats tracks, I suspect medieval generals did the same leaving the trebuchets at home until they had need of them rather than carting them around everywhere just in case.