Wouldn't totally surprise me with there being a recently restored preserved
example, but I can't see it being a massive seller.
Would I have one? Maybe, but by no means a certainty.
"John Turner" wrote
It would seem to be a well-regarded loco among some modellers who like
hardcore dirty freight action, but then again, that doesn't translate to
high street sales. I look forward to MRJ's review crew getting their hands
on it - they seem pretty thorough (and often positive) about recent RTR and
there appears to be an LNWR element among them - some kitbuilt Super Ds have
appeared in their pages over the last few years. It would at least look
better on the average "don't care about authenticity, I just buy what I
like" layout when paired with the ever-popular private owner coal wagons, in
a way that nothing in BR livery ever will. Its low-speed hauling capacity
(motor, gearing, adhesive weight) had better be up to the job!
Didn't the Super D share the same boiler as the "Greater Britain"
class... a unique 2-2-2-2 which, if the separate valve gear were set
incorrectly could slip and remain stationary with the front drivers
going forwards and the rear in reverse.
What an opportunity for DCC...
No. The original 3-cylinder compound 0-8-0s did use the GB boiler
(complete with combustion chamber half-way along the barrel). They
were the A class, IIRC. A larger boiler (without combustion chamber)
went onto the four-cylinder compounds, some of which got a larger
boiler and became 2-8-0 compounds. Later the 3-cyl and 4-cyl
compound 0-8-0s were rebuilt with 2 inside cylinders and boilers
like the 4-cyl compounds (these may have all formed the C class -
I'm working from memory here!), while some got bigger boilers
still to form the Ds. New-builds of Ds with superheaters became
the Super Ds. The boiler of the super Ds were a lot bigger than
those of the original compounds.
Not independent valve gear: Earlier Webb compounds had separate
sets of valve gear for HP and LP (which had its own problems)
but from the Teutonics on he used a simple slip eccentric for
the LP gear. Problem was that occasionally when backing onto
a train the slip eccentric would remain in the back position, and
if the HP cylinders couldn't move the train forward enough to
reverse the LP gear before the HP exhaust hit the LP cylinder..
well, you had a problem.
Nice opportunity for sound: I've read a description of a Webb
(3 cyl) compound starting away with "a faint whistle from the
chimney, followed by a series of immense, wide-spaced cracks"
as the LP cylinder kicked in..