1938 Stock Preseved by London Transport Museum Preserved 1938 stock near Croxley Green, heading towards Watford. Preserved 1938 stock near Croxley Green, heading towards Amersham. Preserved 1938 stock near Croxley Green, heading towards Amersham. Preserved 1938 stock approaching Harrow-on-the-Hill. Preserved 1938 stock approaches Harrow-on-the-Hill alongside an S8 stock.