Boiler type most in use

I was thinking degree of superheat. The surviving Std 1 boilers are a mix of two row and 3 row superheater boilers, the latter being the increased superheat introduced about 1944, but I think all or nearly all the Std4 have 2 row superheaters. I believe the two row superheater also permits each element to be removed without disturbing its neighbour and I don't know if that would have advantages today.

 

Thinking somewhat laterally... what about the Sentinel vertical boiler? Not too many preserved locos, but lots of steam waggons!

 

They generally have a different boiler to the locos though and I think that there are three different boiler types for the few steam locomotive survivors. No doubt 'Eightpot' can give chapter and verse.

 

I believe austerity 3809 is getting a spare boiler off another as an interim measure as the overhaul of its own boiler was going to take longer. Not sure if that is still the current plan, but it does indicate that there may be at least one spare austerity boiler knocking about. The problem I see with keeping a spare boiler ready 'on the shelf' as a commercial enterprise is that it's a huge speculative investment and many owners will want to spread the overhaul cost by doing a lot of work themselves and spreading the specialist stuff over time. So it's pure fantasy really. If you owned a small fleet of them it would make more sense, but does any one organisation own more than 2 or 3?


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The pressings are the same - just different hole arrangements.

Most of the GW 2 cylinder locos are fine with the simple 2 row superheat & on heritage lines there is little advantage in anything more than that. (1501 is unsuperheated & fine as a piston valve loco).

The GW standardisation is actually even better than it sounds as, for example, the steel door plate pressing for a No 14 (Manor) is the same as a No 10 (94xx & 2251), whilst a No 4 boiler is understood to be a shortened No 1 making it likely that the doorplate, throatplate & front tube plate are common pressings & possibly the copper plates too.
With these numbers of boilers surviving it must be worth having the plate formers available and some benefit of scale should bring cost advantages over one offs.

Financing a stock of unsold plates might be difficult but with increasing experience & planning, identifying the need for these in good time should be the norm & they are only required for major repairs.