I found a very poor copy of the installation manual dated 1990. To remove the filters.
“To access the filter bags, remove the dome, the plate on which the motors is mounted is hinged for convenient access. Two wing nuts secure the plate. Remove the wing nuts and prop up the motor plate. The filter bags are then in view. If the bags need replacement, unfasten the straps on the top of the filter from the bracket to which it is secured. Releasing the bag it will allow it to drop for removal through the trash door area. Reverse procedure for replacement. “
These vacuums are probably the worse design. To clean them it’s a filthy mess, you have to use a toilet brush mounted on the end of a stiff hose working it up and down inside the filter bag the get them clean. Monorail used a European short drop
coin mechanism that you could only get from Monorail. We converted all of ours over to long drop electronic
coin mechanisms. I don't remember what what year Monorail went out of business. I'm thinking maybe 20+ years ago.