[GS] Canals, rivers and roads

[Trav'ling Canuck]

Actually, I noticed in the screenshots that the districts themselves didn't have railroads, but still used normal roads, so I'm assuming they're not just a graphic update.

They might be tied to the new resource system, boosting the production of relevant mines when connecting the mines to an appropriate Industrial Zone, and having a maintenance cost per tile. The maintenance cost being the reason why you'd put them through a mountain. Maybe the mines even auto-connect themselves, the same way Traders auto-connect cities? Alternatively, there's no maintenance cost, just Builder/Engineer charges to lay railroads, which again would be a reason to pick the shortest available route..