Two overhead cranes service the Laboratory. Each has a 25 ton (222 kN) main hook and a 5 ton (44.5 kN) auxiliary hook with clear heights of 32 ft (8 m). All four hooks can be raised at either 6 or 20 ft/min (1.8 or 6.1 m/min).The bridges of both cranes can travel at either 25 or 80 ft/min (7.6 or 24.4 m/min) along the length of the Laboratory. Hook trolleys can traverse their respective bridges at either 20 or 63 ft/min (6.1 or 19.2 m/min). The cranes are remotely controlled and can operate in unison or independently of each other.