BR Standard Class 9F (Franco-Crosti Boiler System)

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.
== Production ==
Ten of the BR Standard Class 9F locomotives, Nos 92020-9, were built with Franco–Crosti boilers in 1955. Like the German 50.40 these were 2–10–0 tender locomotives with a single feedwater heater under the main boiler.
== The About ==
Ten of the BR Standard Class 9F locomotives, Nos 92020-9, were built with Franco–Crosti boilers in 1955. Like the German 50.40 these were 2–10–0 tender locomotives with a single feedwater heater under the main boiler.
The standard chimney was still used for exhausting smoke from the fire box. The steam chimney was located on the right-hand (fireman's) side, just forward of the firebox, this can be seen in the photograph, smoke from the chimney and steam from the right-hand side. When running at speed the updraft on the smoke chimney was all that was needed. However, where more power was needed steam would be sent to the Blast Pipe to draw more air through the firebox. The Crosti preheaters provided less improvement than had been expected, and were a problem for maintenance, owing to acidic flue-gases condensing in the feedwater heater and causing corrosion. All were converted back to a more standard form within a few years, the preheaters remaining in place, but blanked off.
== The Franco-Crosti Boiler ==
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.
== Performance ==
The Problem why these 9Fs had failed miserably was because of the crew, the crew had hated these engines because they constantly had a lot of noxious fumes coming at them mainly because the steam that was coming out of the sides of the locomotive and not out of the standard funnel, the Franco-Crosti Boiler Versions of the 9Fs were hated so much, that the people and crews gave those 9Fs the nickname of "Frankly Crusty" based on the Boiler System "Franco-Crosti" by changing the words around to making it rhyme with Franco-Crosti.
== Results from the Performance Issues ==
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 crosswind, 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 thus, it resulted in that their power classification was reduced from 9F back to 8F.
== Withdrawal and Disposition ==
No. 92028 was the first Franco-Crosti 9F to be withdrawn in October 1966, No. followed in August 1967, with the remainder being withdrawn en masse in November 1967. All of the 9Fs that were modified with the Franco-Crosti boiler system had been scrapped, with only the regular 9Fs surviving into preservation.
== Stock list ==
Image	Loco No.	Build date	Manufacturer	Status
 	92020 	1955 	Crewe Works 	Scrapped
 	92021 	1955 	Crewe Works 	Scrapped
 	92022 	1955 	Crewe Works 	Scrapped
 	92023 	1955 	Crewe Works 	Scrapped
 	92024 	1955 	Crewe Works 	Scrapped
 	92025 	1955 	Crewe Works 	Scrapped
 	92026 	1955 	Crewe Works 	Scrapped
 	92027 	1955 	Crewe Works 	Scrapped
 	92028 	1955 	Crewe Works 	Scrapped
 	92029 	1955 	Crewe Works 	Scrapped
Category:Franco-Crosti Boiler System
Category:Steam locomotives
Category:British locomotives
Category:Tender locomotives
Category:2-10-0 steam locomotives
Category:2-10-0 locomotives
Category:Scrapped locomotives
Category:Experimental locomotives
Category:Crewe Works locomotives
Category:4 foot 8 1⁄2 inch gauge
Category:Standard gauge locomotives
Category:Built in 1955
Category:Ten-coupled locomotives
Category:United Kingdom
Category:Scrapped steam locomotives
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Category:British Rail locomotives
Category:2-10-0 locomotives
Category:British steam locomotives
Category:British Rail Standard Class locomotives
Category:BR Standard Class 9F locomotives
Category:Locomotives involved in rebuilds
Category:Rebuilds