Why can't I build railroads sometimes?

[Dimension]

Heh... I don't see what all the complaining is about. I love Civ3. It's really nice that they removed and simplified certain elements along with adding things, so Civ3 isn't just a more complex version of Civ2.

I do miss my spy foils, but that made things a little too easy I suppose...

[Dimension]

I think it might actually have something to do with culture and territory. All of the times I've been unable to build railroads, it's been outside my own territory. I think it may be that you aren't allowed to build railroads too close to another civ's territory.

This doesn't explain why two different times I WAS able to build a railroad once I built a fortress (on the same turn, so there was no buildup of culture that would cause the territory to be closer to my empire while I built the fortress).

Currently, there is an area where I can't build railroads near the Romans. You can see that I have used groups of workers to backfill a railroad to get my Cavalry home to heal quickly (and the ubiquitous army of Knights that just won't die). I have extended the railroad several squares this turn, but it won't let me build any farther to the north or east.

[Wernazuma III]

It's a bug, don't know, it sometimes occurs to me. I can build a railroad and on the very next tile it won't work. It generally does work after saving, quiting and loading though, at last after a few turns it's OK again...

[Dimension]

Of course, this also doesn't explain why last turn I was able to extend a railroad all the way up to the edge of Iroquois territory. I razed an Iroquois city in the square just above the cow, and build a railroad all the way to the edge of their territory then made peace.