Ole Rosted schrieb:
> I found a danish edition of "The Guinness Book of Records" published
> 1967 on one of my shelves last night.
> In it it says, that Virginia Railway used a four cylinder 2-10-10-2
> "compound" loc. in 1918. Wooow!
> I don't know what "compound" means. Could mean mallet. This monster -
> I guess - couldn't be run without some form of a "hinge"/articulation.
> Is there a pic of this - presupposed - beauty somewhere.
> Is there a model HO, N, Z or whatever?
> regards Ole Rosted, Denmark
"compound" means that the steam expansion does take place in more than one
cylinder.In ships you find triple or quadruple expansion steam
engines;compound locomotives usually have double expansion;i.e.the steam works
in two cylinders.
The danish "P" is a fine example of a 4-cyl.compound locomotive,as the bavarian
S 3/6 is a german compound locomotive.The steam enters the (smaller) HP cylinder
and decompresses from,e.g.15 at to about 6 at.These 6 at will do their work when
decompressing in the (big,as the steam volume has increased now)LP (low
pressure) cylinders.So you can distinguish the LP from the HP cylinders by their
The Virginian articulated will surely have the (big) LP cylinders in the front
gear,which means this arrangement is a "Mallet".The US railroads mainly used
compounding in articulateds,because they objected to cranked axles,whilst
european constructions proved that they could run over a million km without
cranked axle problems.
One reason US-railroads used simple expansion articulateds more frequently than
compounds is the size of the LP cylinders,which gave a "natural barrier"
to the development.Another reason for the more frequent use of (less economical)
simple expansion on US railroads is the fact that coal is so abundant there,that
the coal price was no real important cost factor compared with e.g. maintenance
Hope,I didn't "over-answer" again...