I totally agree with Woodie it is a question that keeps being asked so it is good to bring this thread back.
I have used several ways to weather my track.
On my N Scale SFRSD layout I have mostly used Micro Engineering Rail Weathering solution with very good results. It gives a nice grey black colour that I wanted.
This is a turnout on my Lost Creek RR
Around the turnouts I use flat black, rust and flat gull grey to make them look like they are well used and have been worked on by track gangs.
On my Lost Creek RR I have hand painted all of the rail with Tamiya Red/Brown, and Tamiya Tuscan Oxide Red and just blended them in all along the rail as I go.
For my Ties I painted them all by hand using a variety of colors. Tamiya Flat Gull Grey, Grey, Earth and mat light brown. I did them all at random intervals and thinned with alcohol so that the colors flowed and did not block out the detail cast into the ties.
The final coat was a diluted wash of India ink in alcohol.
Did I just say final well on some of the ties I went back with some furniture stain and just touched up some of the ties to make them look different and as if they have been replaced some time.
I also painted all of the tie plates rust before the wash of black.
I am liking the ideas I am seeing here. First, I spray the rails from the side with any red oxcide primer I have on hand, then spray the ties from the top and lightly on the sides with Model Master's Light Earth #FS 30140 spray. After that I make up several acrylic washes from the yellows to brown to grays (Barnwood is a good one). Each tie is hand painted (not too time consuming since I build shelf and mini layouts), and when dry with the tie colors alternated, it gives a good appearance. I finish off with sifted decomposed granite and try to bury a lot of the track, but leave some exposed as well. I am getting ready to trash the layout in the photos, so I thought I would share before it is gone.
Not sure if these photos will show or not. One more:
That's what I'm up to. I'm going to start a new mini or shelf layout, and I will need to recycle some of those turnouts and repurpose some of the structures as well. My budget does not allow for any new train purchases this year.