These wagonways went out of use after the fall of Roman Empire, and managed to return only after increased trading and early industrial efforts of European Renaissance. By 18th century, every mine in Great Britain had its own simple railway network, with horses pulling carts from mines to factories. Changes to this kind of transport came in 1774 after the world found out about James Watt incredible discovery – stationary steam engine. As he protected his patents forcefully, the true widespread work on steam powered locomotives started only after his patent lapsed in 1800. Several inventors started working on improving Watt’s design, most notably designing non-condensing high pressure chambers that enabled engine to convert more steam’s power into mechanical energy.