Sentinel Diesel No. 24 is an interesting example of the change-over by a locomotive manufacturer from steam to diesel.

This first-generation diesel is powered by a Rolls Royce six-cylinder engine of 173 hp.  Rebuilt by Thomas Hill / Sentinel in 1967, under works number 188C.  No. 24 arrived at Quainton in December 1987 from the Booth's scrapyard having spent its final years at CEGB's Stella North Power Station.