Is there a way to do it? I don't usually bother with forts, since if a province is taken I just take it back. However I do want to defend my colonies, because over there if it's taken by the enemy and I take it back, then it no longer acts as a colony, but as my own province and it means the rail network has to be developed on it from scratch.

For this reason, I usually put heavy artillery in my colonies and would love to be able to build forts there as well. But I just can't seem to do it since my engineer can't go there. Is there any way around it?

Thanks.

In essence it means that you can get all its resources every turn for free without worrying about building a rail network and without taking up transport capacity. So it is good.

(the initial investment is much smaller than building the rail depots, ports... etc).

The only problem is not being able to build forts, because as I said once a colony is taken you can only take it back as your own province not a colony, which is very annoying.

I never bothered with forts much, but on my latest run playing iron mode (no reloads) on Hard I saw they could be useful to defend colonies. The inability to do so was annoying. I lost one colony and then had to divert one engineer to build a network so I could get my resources back.

Anyway, it seems you can't upgrade forts, so I marked your post as solution.

'Preciate the Solve. The Colony system in IMP1 makes resource gathering easier. But it makes keeping Colonies safe bothersome. I've had a lot of Paddlewheel boats around Minor Nations trying to keep landings. And one hole and the AI seems to land there.
As for forts, I like them when they block sea landings. I've only once seen the AI with a landing force large enough to take a level II fort with a couple cannons. For some reason, during that particular game, the AI had a huge fleet. I'm usually paranoid about my Capital Waters and have a huge fleet. The AI actually was able to defeat my home fleet. Then land a large army. It was kind of neat.

As for the domestic products, IMP2 has the type of system that must make sense to you.