BR Standard Class 9F 92020-9
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
| No. | Built | Converted to conventional | Withdrawn |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
No. 92028 was the first Franco-Crosti 9F to be withdrawn in October 1966, with 92027 following in August 1967, but the remainder were withdrawn en masse in November 1967, all were scrapped, and none had survived into preservation.
| Year | No. Withdrawn | Nos |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
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Wikimedia Commons has media related to BR Standard Class 9F (Crosti boiler). |
- 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.