 Innovations in Newcastle and surrounding areas included the development of safety lamps, Stephenson's Rocket, Lord Armstrong's artillery, Be-Ro flour, Joseph Swan's electric light bulbs, and Charles Parsons' invention of the steam turbine, which led to the revolution of marine propulsion and the production of cheap electricity.In 1882, Newcastle became the seat of an Anglican diocese, with St. Nicholas' Church becoming its cathedral.Newcastle's public transport system was modernised in 1901 when Newcastle Corporation Tramways electric trams were introduced to the city's streets, though these were replaced gradually by trolley buses from 1935, with the tram service finally coming to an end in 1950.