The gatehouse contains a working drawbridge and portcullis. It also gives the guards somewhere to go for a cuppa. The portcullis grating slides vertically up and down in the tower. It's made from a wire mesh barbecue grille, glued into a plywood frame. A sprung lever on the top of the tower holds it in the raised position, or allows it to drop sharply.
Portcullis uprights rise through the gatehouse floor when it's raised.
It's worked by a pinion and wooden rack on the left upright. The blue shaft with red handle works the portcullis. The blue gearwheel on the right has a spring ratchet, to hold the drawbridge up. The red handle sticking through the wall works the portcullis. The curved walls of the gatehouse are made from MDF strips.