What gauge nails are used to mount the ez track sections
Don't use nails. You take too much chance damaging the track. There is no support under the track to keep an over tight nail from bowing the piece and causing dips or gauge of the rails.
Use a glue of your choice. Anything from carpenters glue to hot glue will work. It just depends on the surface you are working on as to what is the best choice.
What my friend Bill does is after he lays the track the way he wants it he draws the out line of the road bed and the layout,removes the track and glues short pieces of cork roadbed where the nails would go.one the glue dries he puts the track back and pushes track or small finishing nails through the nail holes into the cork.
If your wondering how well that works ,Bill's layout has been serving show duty for the last 3 years with out one piece of track coming loose unless he wanted it to. By the way we used this same method on our TTRAK layout for roughly 5 years while using KATO track.