Disgustipated
Deity
+1 Railroad graphics should be improved
+1 Railroads should provide some small increase to production, most logically to Industrial Zones, Harbors and Spaceports, possibly to mines and lumbermills
+0 Environmentally impact should be adjusted. I think it is just fine where it is at.
As to the OP question "Railroads worth it?", for me it is a solid "yes." Surely not for the min/maxer, but I'm a builder/roleplayer and I believe that railroads significantly add to those aspects of the game.
Built them again in my current Germany game. For longer drawn out games I see value in them. I agree about the graphics, especially regarding districts and wonders. No way to tell if there's a RR there. A small production boost would be nice, but the gold isn't insignificant.
As for cost analysis, I was very conservative using 5 above, but really it seems like 10+ gold increase in some of the longer trade routes. I haven't even bothered testing it on internal trade routes, I assume they provide gold, but I'm not sure. From a cost analysis standpoint, they seem worth it assuming your game goes on long enough. But for any early cultural or domination/religious victories I do, I probably won't bother.