-=> Quoting Reggie Arford to Gregory Procter <=-
 GP>A modularised steam loco could be a workable complex
 GP>machine in the 1990s, and a
 GP>Diesel would be an unworkable simple machine in the 1920s.
 GP>The only diffficult and specialised part would be the boiler.
 RA> Oh? Most buildings, esp. houses, have a boiler in them.
 RA> Sometimes it is just used to heat hot water, sometimes as an
 RA> actual boiler, but the design is parallel. What's so hard?
 RA> Reggie Arford
 RA> ___
 RA> X SLMR 2.1a X Contentsoftaglinemaysettleduringshipping.
 The problems of making locomotive boilers today, stem from the fact that
 they are are rather larger than house boilers, but more particularly they
 run at higher pressures, move around more and are restricted in size,
 particularly in cross section (loading gauge)
 I don't think there are many presses capable of pressing the throat plate
 of a traditional boiler anymore, or roller presses to curve the boiler 
shells.
 Loco boiler designers were forced into creating complex firebox shapes due 
o
 the limited space for ashpan, firebox and waterspace. The traditional Steam
 loco design usually put a large wheeled truck under the ashpan to really
 restrict the design.
The hypothisised modern steamer could be a Bo'Bo' or a Bo'Bo'Bo' with almost 
no
restrictions for the firebox between rail and loading gauge.
A major limitation with steam boilers, is that the energy used to heat the 
water
from air temperature to boiling point is virtually unrecoverable. 
Theoretically,
the higher the steam temperature/pressure the more efficient the boiler will 
be,
because the percentage of energy used in heating the water to boiling point 
will
be smaller at higher temperatures.
The high pressure boiler needs thicker steel plates and more specialised 
tays
etc.
Greg.P.
  
... Catch the Blue Wave!
--- FMail 1.02
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