I was having the exact same problem, man. To fix it, I had to download NAM again with the RRW_textures files and, unfortunately, start over the city I was building, because it just wasn't registering the rails I was laying.
In this first image, you can see that there is just 4 rails in the Heavy Rail Tile Count, but of course there is more.
On Nº2, the rails doesn't appear on data.
But just in this city happened this and any other new one everything is normal.
I'm sorry for the English, I'm from Brasil.