I was lucky enough to visit Lostwithiel box a couple of years ago. Its a one-man operation but towards the upper limit of what can be safely achieved due to having not just the lever frame and level crossing to manage (on a road that is quite busy!) but also a small NX panel controlling the Bodmin and Largin area. With two trains per hour throughout the day - a third at certain times - plus freight to the Fowey branch etc which has to run round in between main line traffic, the signaller is certainly kept on their toes! Plus the length of some of the ‘pulls’ requires significant physical strength. Economy of movement and energy management indeed.