That's a matter of a pinion... This large axle-mounted gear indicates that the 1904 Stothert and Pitt crane belatedly returned to its birthplace see image 41493 could self propel - albeit slowly. The steel plates beneath seem to be in informal storage.
Location: Bath Green Park
Original line: Stothert and Pitt
Photographer: Ken Strachan
Contact photographer: Ken Strachan
Photosets: Somerset and Dorset
Date: 26/12/2013
Image number: 45786