On Fri, 29 Jul 2011 07:33:03 -0700, Andy Dingley wrote:

On Jul 29, 12:21Â*pm, Andy Breen wrote:

I'm pretty sure the (main-line) use of flue-type fireboxes

What's a "flue type firebox" ? If you mean a flued boiler, then they
went out very early on, as they had so little heating area. They were
only practical for Lancashire boilers because they could be much longer
and were followed by economiser chambers too. Even the Lancashire was
usually a Galloway boiler in later years, with cross- tubes.

Boilers with a single flue (straight through or return type) lasted in
new-builds through to the early 1840s for main line use (Stockton and
Darlington Railway, Clarence Railway, West Hartlepool Railway..). They
were cheap - and in fact several batches of locomotives with flue-type
boilers were built for the S&D after they'd had a period of building
locomotives with tubular boilers (both straight-through multitube and
return-flow multitube).

The later multi-tubular version is generally called a "launch-type" or
gunboat boiler. These had some use for small ships, and for small narrow

Or, in marine use, a "locomotive boiler".. :-)

gauge locos - Arthur Heywood in particular used them. They have the same
cylindrical furnace with only a small ashpan beneath the grate, but as
they have firetubes similar to a conventional loco boiler, they also
have plenty of convective heating area.

This was what I meant - a cylindrical flue-type firebox, feeding into
either straight-through multitubes (Dodds, Hackworth - both brothers,
Adamson, Heywood..) or a return-flow arrangement (Hackworth). These were
built for main-line use through to the later 1840s on the S&D (observe
Derwent, built 1845 with a flue-type grate feeding a return-flow multitube
arrangment..). Industrial locomotives with this arrangment continued to be
built considerably later, and some of these ran for significant distances
over main lines (the West Hartlepool railway outsourced much of its
mineral traffic to colliery owners using their won engines, for
example..).


Launch boilers were never used on mainline locomotives, as they have too
little radiative heating area (i.e. firebox surface) and so their power
output is low, even if they're reasonably efficient overall.

Universal until the very end of the 1840s for mineral traffic on the S&D
(and used for several fast passenger engines) - these engines lasted past
the 1870s in main line use.. Also used on several other companies main
lines (Llanelly Railway, West Cornwall Railway, West Hartlepool Railway,
Clarence Railway..). So certainly not "never used"..

They were
used in later years by both the LNWR for a class of small shunters and
also by the L&Y for the 0-8-0s you mention. Neither of these were
long-haul locomotives, but rather shunting within a yard and with pauses
between moves to recover. The L&Y locos had reasonable tractive effort
(cylinder size and pressure), but couldn't sustain this for any long
period, owing to the lack of firebox evaporative capacity. There's also
a suspicion that they were more the result of lobbying at Horwich by
local makers of corrugated furnaces for the mill engine trade. Certainly
not a sucessful or repeated experiment.

Agreed - though their building also followed a couple of very nasty
firebox collapses traced to problems with staying. They were an attempt
to do away with staying altogether.

--
Andy Breen, not speaking on behalf of Aberystwyth University "The
internet, that wonderful tool for bringing us into contact with things
that make us wish we could scrub our brains out with dental
floss.." (Charlie Stross)