Steam design challenge 2000

["Kevin Sewell" <kevinsewell@optusnet.com.au>]

I'm ¾ through reading a very interesting book called The Illustrated
Directory of Trains of the World by Brian Hollingsworth. It doesn't cover
every loco ever built around the world but starting with the very first
locomotives it documents the progress of locomotive design, and goes into
interesting detail about why a loco was included and what innovative
features or technical reasons make it better (or different) to its
predecessors. From the simple 2 cylinder jobbies to, complex 3 & 4 cylinder
compounds, right through to Mallets, garretts, steam turbine, and the US
monsters. Also from the first diseasal and electric, to TGV, ICE, Shin
Kansen, and current US diesels to 1998.

While the book has its shortfalls (fancy including Vic S class or SA 500
class but not 38 class!!) each improvement set me to thinking how would we
design a (reasonably conventional) steam loco today knowing now what we know
about design.

So, here's the challenge. What design features should we include which
satisfy the following restrictions? We're not after exact dimensions or
measurements, and the fundamental rule is that every inclusion must be fully
justified. The one thing this book highlights is that there has always been
more than one way to kill a cat, so you must justify your inclusions. For
example, round top vs. belpaire; 3 vs. more driving axles; 2 vs. more
cylinders; type of fuel; means of lubrication; ball vs. roller bearings;
simple vs. compound etc. etc. Let's not get too carried away with fluid beds
or gas/steam turbines but keep it fairly conventional. Cost is an issue only
to the extent that expensive features will need to be justified in a payback
sense. Ultimately we're after a design which is supremely efficient.

? Assume high quality maintenance in a quality servicing centre and a ready
supply of parts.
? Assume current mainline gradients and speed restrictions can only be
improved by 5% (and not more than XPT permissible speeds).
? Assume maximum possible convenience for crew and servicing staff.
? Assume current NSW loading gauge can only be improved by 5%
? Assume able to haul passenger trains of 500 tonnes on Sydney - Melb or
Syd - Bris routes.
? Assume carriages will perform to same standard as loco. You may also want
to spec carriages. In many cases around the world the carriages and loco
were a matched set (e.g SOP, Coronation Scot, SP Daylights)
? Assume current comparability between cost of coal and fuel oil. Ignore
acquisition/delivery costs.
? All tooling and technology and materials existing in 2000 are available to
us.
? Include specs for the tender to match the loco.

I believe its a cop-out to say "just go with diesel". Experience on other
railways in the world indicated (particularly in the earlier days of diesel)
that good steam design made dieselisation marginal. What can this learned
forum come up with? If it makes the challenge any easier, start with a 1930s
design (38 class) and improve on it. Or start from a blank drawing board. Go
to it! That's your Christmas holiday challenge.

PS. There's going to be many different opinions here. Can we please not
degenerate to a petty shitfight about 21 inch vs. 21¼ inch cylinders?