i'm thinking that you might want to cut the brown and grey strips and sew them together in a big long strip. Then you have 2 options:
1) slice the strip and sew in a silver strip perpendicular to the others. I think this is what you are thinking and wondering how to keep the rails in line so you could try option 2:
2) Make a tube out of the silver, don't cut the other strip and just sew it down on the first strip like applique'. This way everything will line up, just like you 'nailed down the rails' !