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Domes on A3s

Posted: Fri Feb 02, 2018 2:13 am
by Graeme Leary
I note in RCTS 2A (p44) that 38 A3s were constructed with round domes (Diagram 94HP) and 72 with banjo domes (HP94A). There is further information concerning interchangeability and some locos that only ever had one or the other (but not both) types.

Is there a list of which of the class had the round and which had banjo domes when first built? I'm specifically interested in which diagram domes 'Bayardo'/2578 and 'Victor Wild'/4474 had in 1930 and the dates on the Summary sheet showing when each of these had boiler changes (Bayardo to HP in 5/28) and Victor Wild to HP in 10/42 would suggest to me they both had HP94A/banjo when first built. Probably bleedin' obvious but confirmation greatly appreciated.

Many thanks,
Graeme Leary

Re: Domes on A3s

Posted: Fri Feb 02, 2018 3:30 am
by Woodcock29
Hi Graeme
In your comments above you seem to be mixing up boilers with locomotives. A lot more boilers were built than locomotives as boilers were condemned long before locomotives, so locomotives needed new replacement boilers and of course boilers also got switched around between locomotives during overhaul. There were only 79 A1s/A3s actually built.

The first locomotives with the banjo dome were the 9 in the Windsor Lad series built 1934-35 - these were built as A3s (the final series of locomotives built), as were the preceding 18 but these had round domes when built (built 1928-30). The domes on the Windsor Lad series were the only true banjo domes as those boilers built after that had streamlined domes where the sides were flat tapering to the rear, rather than the banjo shape (10 later boilers built under Thomson's reign did have round domes).

All earlier locomotives were built as A1s with 180 psi boilers and of course had round domes - these were distinguishable by not having the superheater covers on the rear of the smokebox behind and below the chimney. All A1s, other than Great Northern, were eventually rebuilt to A3s with the 220 psi boiler.

Both Bayardo and Victor Wild were originally A1s so had round dome when built and even though Bayardo was rebuilt as an A3 in May 1928 neither the banjo or streamlined dome would have been fitted as these were not introduced until 1934 and after. Victor Wild was not rebuilt until Oct 1942.

I trust this all makes sense.

Andrew Emmett

Re: Domes on A3s

Posted: Fri Feb 02, 2018 10:12 am
by jwealleans
Andrew has it right. Hornby seem to have a bit of a thing for the streamlined dome as every one of the A3's I've worked up for Grantham has had to have one removed and a round one substituted. Mr. King of this parish does a very good resin replacement.

Re: Domes on A3s

Posted: Fri Feb 02, 2018 7:38 pm
by Graeme Leary
Very many thanks Andrew and jwealleans - answers my query very nicely (so, in my case, look for a round dome model).
Graeme

Re: Domes on A3s

Posted: Fri Feb 09, 2018 4:03 pm
by 4812
Weren't there 2 varieties of cover for the 'banjo dome' - the early one which had a round dome with a fat tail, and the later which had the plan of a violin case, with straight sides?

Re: Domes on A3s

Posted: Fri Feb 09, 2018 4:47 pm
by mick b
4812 wrote:
Fri Feb 09, 2018 4:03 pm
Weren't there 2 varieties of cover for the 'banjo dome' - the early one which had a round dome with a fat tail, and the later which had the plan of a violin case, with straight sides?
1. is the Banjo Dome

2. is the Streamlined Dome

Re: Domes on A3s

Posted: Sat Feb 10, 2018 1:41 pm
by Woodcock29
4812 - see second paragraph of my post above
Andrew

Re: Domes on A3s

Posted: Sat Feb 10, 2018 3:19 pm
by 4812
Thank you Andrew. The banjos must have been replaced quite quickly, and it was odd that Triang chose to put one on its A3 moulding.

Re: Domes on A3s

Posted: Sat Feb 10, 2018 9:03 pm
by JJC
Regarding the banjo / streamline dome. What you see is only a cladding cover, so was the change in its shape caused by a design change to the actual dome on the boiler or was it only the cover that was altered? ( I seem to remember reading somewhere that it was only the cover that changed and the reason was to cut manufacturing costs )