I like it, I think you can put it in
Not yet.
This feature is
too controverse to implement it without further feedback from the team.
Maybe some other team member will have a veto against this feature.
(Which I could understand.)
It is definitely very
useful on gigantic maps and a lot of
fun.
But it is also absolutely
historically incorrect for that time period.
Although because it really should require an advanced late-game tech; maybe would be best to add it when we have Technologies.
Trains are not that easy to build and cannot be bought.
You can only build them in cities where you have a train station.
And a train station again, has prerequisites, too.
Also, they are expensive to build.
(Railroads are also much more expensive than normal roads.)
But later, when we
have technologies, we could surely have a tech as prerequisite for them.
But, do you think the AI can be trained to work with this?
It should be able to generally handle this, but of course not as good as human players.
(But maybe a few improvements for AI might really be needed.)
One issue would be making it build a single direct rail line between inland cities, not cover every tile with rails like it does in Civ4.
Don't see a big problem with that.
AI tends to connect cities quite well with roads and railroads.
But generally you are right, we would need to test if that AI needs improvement for that feature.
I think it could also be ok to simplify things by letting units use rails as in Civ4.
That is what I
explicitely do
not want.
The Civ4 system is incredibly
boring to me and also extremely
unatmospheric.
Colonization "thinks" in transport units and I would like to keep that.
Railroads are only useful for trains and do not affect movement speed of other units.
(For other units railroads are like normal roads.)