After play some scenarios I am a bit confused, you have some units supposed to repair the rail line but I only can do that with the railroad engineer units so what is the purpose of the construction engineers? or must I do a specific action to use this construction engineers?, thanks in advance!.
Best
If I am not mistaken (it has been a while), the construction engineers help with defense if a stack is assaulted. I can't remember if they actually do any fortifying or if it is just a bonus to the defense - but I am pretty sure the specifics are listed in the manual under engineers.
I'm pretty sure only RailRoad engineers can repair the rail lines. Construction Engineers cannot.
As VM says above they benefit defense but I'm sure I read somewhere in the manual that they are also useful when attacking enemy fortifications. I think if you attack an enemy fortified hex with a force including a Construction Engineer unit it reduces the effective level of the fortification by 1 (for that attack only - I don't think they actually destroy the fortifications).
I should say that what I've said above is just off the top of my head so I apologise if anything is inaccurate.
Andy
They also reduce the movement cost for rivers if you start in the hex with them.