I think I used a photo of 1959 Stock in UndergrounD at Amersham on braking tests. I wonder if they were seeing how fast the new trains would go back in '60? From experience in Picc days as s a commuter, they seemed to be able to travel 'fast enough' between Acton and Hammersmith.
Vintage transport magazine Deputy Editor; Journalist; Author. Died 2012.