When the leviathans of the steam age were built at Swindon works they had to be tested. A mammoth 'rolling road' was built inside the factory for this purpose and here we see unique footage of King George 1V 6003 undergoing preliminary tests before entering the line. The only thing missing here is the sound of the fury of a tethered steam giant thrashing away. The first of the four cylinder Kings was No. 6000 King George V, it entered service on 29th June 1927. Within a few weeks it was on its way to the United States of America to take part in the centenary celebrations of the Baltimore & Ohio Railroad. It made a very favourable impression with both its looks and performance, taking a 543 ton train from Washington DC to Philadelphia at speeds of up to 74mph. To commemorate the visit No. 6000 was presented with an American brass bell which still adorns King George V buffer beam. The Kings weren't without their problems. Just a few months after the triumphs in America with No. 6000 came a near disaster involving this very locomotive - No. 6003 King George IV. The locomotive derailed at speed, luckily without serious consequences. The cause was one of the novel aspects of the Kings. The plate frame front bogie with independently sprung wheels. Modifications were swiftly applied and the Kings resumed their place at the head of the GWR's crack expresses, such as the Cornish Riviera Express and The Bristolian.