BR Standard Class 9F 92020-9

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Crosti 9F 92021 at Wellingborough shed in 1959, showing the unique layout on the right hand side of the loco
9F 92022 in 1964; the preheater drum had been sealed off in June 1962
9F 92029 in 1964

British Railways Standard Class 9F steam locomotives Nos 92020-9 were experimentally built with Franco-Crosti boilers, thus forming a subclass. All ten were built in 1955 at Crewe Works.

The Franco-Crosti boiler took the form of a single cylindrical water drum running along the underside of the main boiler barrel; the standard chimney at the front was only used during lighting-up, in normal working the gases went through firetubes inside the preheater drum that led to a second smokebox situated beneath the boiler from which there emerged a chimney on the right-hand side (fireman's), just forward of the firebox.

In the event, the experiment did not deliver the hoped-for benefits, and efficiency was not increased sufficiently to justify the cost and complexity. Moreover, conditions were unpleasant on the footplate in a cross-wind, this in spite the later provision of a small deflector plate forward of the chimney. These problems led to the subsequent sealing off of the preheater drum, over the period 1959-1961, and the locomotives were then worked conventionally. As a result of this, there was a reduced ability to generate steam, and so their power classification was reduced from 9F to 8F.

All were fitted with the BR1B-type 4,275 imperial gallons (19,430 l) tender.

Stock list[edit]

No. Built Converted to conventional Withdrawn
92020 March 1955 1961 November 1967
92021 March 1955 1960 November 1967
92022 March 1955 1962 November 1967
92023 March 1955 1961 November 1967
92024 June 1955 1960 November 1967
92025 June 1955 1960 November 1967
92026 June 1955 1959 November 1967
92027 July 1955 1960 August 1967
92028 July 1955 1959 October 1966
92029 July 1955 1960 November 1967

Withdrawal[edit]

No. 92028 was the first Franco-Crosti 9F to be withdrawn in October 1966, with 92027 following in August 1967, but the remainder were withdrawn en masse in November 1967, all were scrapped, and none had survived into preservation.

Year No. Withdrawn Nos
1966 1 92028
1967 9 92020–7/9

Further reading[edit]

  • Cox, E. S. (1966). British Railways Standard Locomotives. London: Ian Allan.
  • Richard Derry The Book of the 9F 2-10-0s ISBN 1-903266-73-4
  • Gavin Morrison The Power of the 9Fs OPC Railprint 2001 ISBN 0-86093-558-2
  • H.C.B. Rogers, Riddles and the 9Fs (Ian Allan, 1982)
  • Nock, O.S. (1966). The British Steam Railway Locomotive. II, from 1925 to 1965. Ian Allan. p. 264–265.