Boiler & Firebox

Steam manifold, complete, ready to fit.

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Boiler and Firebox

The boiler is the normal design with riveted joints throughout, working at 225 lbs. Per sq, in. The shell is of high tensile carbon manganese steel throughout, and the barrel consists of two rings, the second ring being tapered and forming a true cone. The two rings are rolled from 0.5 in. thick and 0.5625 in. thick plate respectively, the outside diameters being 5 ft. 4 in. at the front and 6 ft. 1 in. at the firebox end.

The smokebox tubeplate is of the drumhead type, 0.75 in. thick, and there are 35 large flue tubes 5.5 in. diameter outside, 7 S.W.G. thick and 108 small tubes 2.125 in. diameter outside and 11 S.W.G. thick. The length between tubeplates is 17 ft. 0 in. A 'Belpaire' firebox with wide grate is fitted. The steel wrapper plate is 0.5 in. thick and the inner firebox is of copper and has a 0.625 in. thick wrapper plate. The front of the firebox is extended into the boiler barrel to form a combustion chamber having a 1 in. thick tubeplate. All firebox waterspace stays are of monel metal, fitted with steel nuts inside the firebox. The roof, longitudinal and transverse stays are of steel, the former being riveted over outside the steel wrapper.

The firebox is 6 ft. 9 in. long outside the width tapering from 7 ft. 0 in. at the front to 6 ft. 8 in. at the back, giving a grate area of 36 square feet.

The steam dome contains a 'MELESCO' centrifugal drier. The regulator is of the Superheater Company's multi-valve type and is incorporated in the superheater header fitted in the smokebox. Access to the regulator valves is by a detachable cover in the top of the smokebox.

The boiler is fed with water through two separate clack valves placed on the front barrel, delivering on to two inclined trays, which deflect the incoming water round the inside of the barrel clear of the tubes. A steam manifold is fitted on the top of the firebox in front of the cab, and is provided with separate shut-off cocks to each steam supply pipe as well as a main shut-off valve, this being operated from inside the cab.

Two direct loaded safety valves are mounted on the hind barrel immediately behind the dome. The boiler and firebox are lagged with a light weight Fiberglass mattress.

The material specification on the drawings for the boiler are very high, this may partly account for the low running costs returned by the class six boilers amongst the lowest if not the lowest on record. It is also thought the quality of water available in Scotland which is naturally very pure also contributed to this.

We are determined to have the boiler made, as per the drawing, in Britain, and in a small way we will help invigorate the manufacturing skill base needed to maintain steam engine boilers of all types, keeping it alive and well for future generations.

Historical Notes

The boiler fitted to the clans was a Type 2 and for 72000 - 72009 the boilers were numbered 826 - 835 and boiler 964 was built, as a spare. This was used to speed up the amount of time the loco would be in the works. If any work were needed on a boiler, then they would just swap it for the next one that was ready to be fitted to a clan.

72010 was going to be fitted with Type 2 boiler number 1477. The lot 242 boiler numbers started from 1477 - 1491. These boilers were never built as B.R felt that with the decline of steam that they still only needed one spare boiler for the class.

Held in Store

Main steam manifold complete and ready to fit
Maximum boiler pressure plate, original
Water gauge pedestals originals
Water gauge frames and protectors originals
Top feed clack valves un-machined
One un-machined safety valve body
Fire-hole door handle forgings un-machined
Back head cladding in progress
Boiler pressure gauge new ready to fit
Steam brake bracket ready to fit
Injector steam feed control brackets ready to fit
Pair of fire hole doors
Original firing flap, kindly donated by 6695 Locomotive Group
Fire-hole doors, raw castings

Patterns Held

None

Wish List

Biggest wish of all - the money to order the boiler

Thank You

Gordon Newton at Israel Newton, boilersmiths, who took the trouble to look at, comment on and discuss the boiler drawings. He was very reassuring and could not see any problems, other than the limitations of his crane should we contract him to build it. All the forming for the firebox, which are relatively soft easy curves, could be done and he was confident that anything he couldn't do Pridhams could.

Bob Maxwell who made such a good job of the steam manifold.

The 6695 Locomotive Group (ex G.W.R. 0-6-2 Tank) for donating the firing flap.

Flanging Blocks

Peter Pickering, master steam locomotive engineer, mentioned being shown the flanging blocks for the Clan boilers whilst visiting Crewe works, they were still being used, as weights on a giant press in the fabrication shop. A telephone call to Bombardier started an hectic wild goose chase. The chaps at Bombardier knew about them, yes they were there on the press stamped up 72xxx, but it had all been cleared out just the previous week by scrap men! Despite some frantic phone calls to all the scrap merchants engaged in the massive site clear out it was too late the scrap men were certain that if they removed the blocks, as it was all just steel to them, they were now on their way to Italy in the hold of a ship to be melted down. This tragedy may well prove to be a blessing, the urge to preserve the blocks would have created a very heavy, awkward, storage problem and with modern pressing techniques their practical use to help build the boiler without the press they were designed for they were in all probability obsolete.

How You Can Help Build 'Hengist'

You can make a donation, you can sponsor a part or you can become an active member, for more details email: info@72010-hengist.org or write to the chairman.