Welcome to the forums.
However, to answer your questions we need a little more information. Are the shelves to run trains on (shelf layout) or store trains on for display or just store off the layout? For your cabinets are you thinking of display cabinets to show off train items or storing things above or below a layout?
Think you'll get some answers when we get some more information.
Good luck,
I am looking for ideas, plans or materials with techics to build shelves and or wall cabinets.