Our elementary school has a really sturdy chrome metal clothing rack installed on the back wall of the cafeteria. Maybe about 6 feel long. It has rack shelf on top and then a horizontal bar to hang clothes. (So a metal/chrome version of how you hang clothes in a closet, except this is just on the wall.) There's a big sign and teachers are asked to check with students at least once a week when they are at lunch.
Here's a link
to a picture similar to ours. Note - I know nothing about that company, just using as an example.
Another good option is to buy rolling clothing rack like is used in the fitting room area of retail stores. The kind that is heavy duty and has the wire bin in the bottom for non hanging items. Then you can hang clothes on hangers and put the bulky items in the bin. I've seen those, but not sure of sources. With that kind you can move it around. You definitely want high quality for that. The inexepensive home versions won't last.