There are blackening agents that places like micro mark sell as well. I don't think the oil on the center rail makes any sense,by doing that you are leaving oil on the rail that can collect dust and grit, and if the oil is on the top of the rail it will get on the rollers and also will cause problems with conductivity. I assume they say to do that to try and keep it from oxidizing but I wouldn't do that.
There has been a lot written about making the rail look better, here are a couple of other things
1)Paint the side of the rails with a rust color (make sure to clean the top of the rails)
2)Add extra ties between the metal ones, there are firms that sell wood or rubber ones, or you can make them from appropriate wood.
3)Once you add the extra ties, color them and the metal ties a creosote treated wood color so they match
4)Ballast the track
