The Class W1 No. 10000 ‘Hush Hush’ is the next model to be treated to a steam generator. Bring life and realism to your layout with this terrific model. Hornby Trains Sets. Having completed nearly 90,000 miles of test running since new, Sir Nigel Gresley’s W1 4-6-4HP No. 10000 entered Darlington Works on 21 August 1935 for what was anticipated to be a major overhaul and modification.