GWR Star class 4-6-0 No 4005 Polar Star at Old Oak Common shed in May 1934.

Peter Kerslake says "Built at Swindon in February 1907 Polar Star 4005 participated in the August 1910 exchanges with the LNWR 'Experiment' 1455 Hertfordshire, the 'Star' running between Euston and Crewe whilst 4003 Lode Star was similarly tested against 1471 Worcestershire on the GWR between Paddington and Plymouth. The exchanges showed the superiority of the 'Stars' over the 'Experiments, especially on the GWR line with Worcestershire often failing to run to time, but it has to be remembered that the two-cylinder LNWR locomotives were smaller than the four-cylinder 'Stars'.

Photo: L.R. Tomsett/Rail Archive Stephenson