Adding subroadbed and risers for track elevation

I have cut out the subroad bed out of 1/2" plywood. I use 1/2" plywood to join the different sections of roadbed together, adding strength with construction adhesive and 3/4" drywall screws. Once all the sections were together I add the risers in. They are made from 3/4" plywood. I use 1-1/4" screws to attach them to the stringers and also the road down to the risers. I never use adhesives to attach the risers just in case I have to adjust any elevations.