From Commercial Motor magazine, July 12, 1957:
Specially designed for arduous working conditions, the Hy-Mobil 45, a new mobile crane, is being manufactured by J. Darlington and Son (Engineers), Ltd., Harpurhey, Manchester. Mounted on an ex-W.D. Morris four-wheel-drive chassis, with Edbro-B. and E. twin hydraulic rams, the crane employs a goose-neck main jib pivoted at the rear and working in conjunction with a supporting jib, also pivoted at the rear.
Twin hydraulic rams raise the jibs and serve to distribute the load over the chasis frame. To relieve the front springs of the weight when under load, wedges have been fitted which make the front end solid when 2 in. of spring deflection have been taken up. Three lifting capacities are provided by altering the position of the hook: 45 cwt., 40 cwt. and 35 cwt., the respective lift heights being 17 ft. 3 in.; 17 ft. 10 in.; and 18 ft. 5 in.
Powered by a four-cylindered 3.5-litre petrol engine, the vehicle has a wheel-base of 8 ft. 3 in., with a turning-circle diameter of 52 ft. The gearbox has five forward speeds and reverse, front-wheel drive being optional in all but first and reverse, in which it is automatically engaged. Heavy-duty cross-country remoulded tyres are used.
Gross weight of the outfit is 6 tons 9 cwt., and the overall length 27 ft. 4 in., the tip of the main jib being 10 ft. 5 in. in front of the radiator when lowered. Normal road speeds appy, and the tax is £2 per annum. The price is £975 complete, optional fittings being a perkins oil engine and winch gear.