Wiener lists no less than 24 such systems in 5 different
groups, probably no more than 5 systems were of any real significance...
Transmission by rods located on the axis of the locomotive
- a non starter
Convergent Axles coupled by Oscillating Levers
Of the four systems listed, only the Hagans system
saw the light of day - see http://www.douglas-self.com/MUSEUM/LOCOLOCO/hagans/hagans.htm.
Such locomotives had two sets of wheels, the forward set were
conventional. The rear set was driven by a set of rods and oscillating
levers, which meant that the rear bogie could be allowed to move
laterally. Gölsdorf axles could do the job just as well and the
system was rapidly consigned to the history books. No such locomotives
Convergent Axles coupled through Driven Countershafts
Of the eight systems listed, only the Fink's System
saw the light of day - see http://www.douglas-self.com/MUSEUM/LOCOLOCO/fink/fink.htm.
No such locomotives survive.
Convergent Axles coupled by means of Coupling Bars of
Again of the five systems listed, only the Klose
system was actually incorporated into locomotives - see http://www.douglas-self.com/MUSEUM/LOCOLOCO/klose/klosetothe.htm
Such locomotives were used in the former Yugoslavia on the 760mm
gauge, see pictures on this page http://www.angelfire.com/co3/drustvo/Cira/Cira.html
(classes 189 and 191).
I have used the phrase above which appears in
Wiener's book but I prefer to use 'Hollow Axles'. It seems that Arthur
Heywood was the first to describe and apply such a system - http://www.douglas-self.com/MUSEUM/LOCOLOCO/heywood/heywood.htm
-but the chief patent belonged to two Germans after whom 'Klien-Lindner' axles are now known (and please note that the first of these
two gentlemen is not 'Klein' as frequently appears). The Orenstein and
Koppel locomotives of the Matheran Hill Railway used this system and
were 0-6-0T - see elsewhere
on this site for pictures of them at work. However, the vast majority of
locomotives that used this system were 0-8-0T.
all such locomotives had outside frames - there are more diagrams in
Wiener's book see Bibliography.
diagram below shows how the drive on the outer axles was transmitted
by a pin attached to a large ball to the actual driving wheels, this
is taken from the Du Croo and Brauns book - see Bibliography.
Underneath that is a picture of an actual axle (broken, with contents
exposed) in Java where a huge number of locomotives were so equipped
and a number were still active in 2009.
practice, the original patent covered the basic idea and indicated
that the outer axles should be connected to pivots in the centre of
the locomotive to (hopefully) ensure that the outer axles behaved
themselves when curves were exited. In practice, leaving them to sort
themselves out passively was soon found to be inadequate and
modifications had to be made. In the case of Orenstein and Koppel
locomotives this meant adding springs, this is taken from the OK book
- see Bibliography.
and for Maffei (and later
related Du Croo and Brauns locomotives) this meant coupling the outer
axles with a central pivot so they acted on each other, this is taken
from the Du Croo and Brauns book - see Bibliography.
manufacturers of such locomotives (eg Borsig, Hanomag, Henschel and
Jung also found in Java) had their own modifications but it
would need one of them to be jacked up to examine the details and
apart from a Borsig diagram in Wiener's book I
have yet to see details published. I have too many pictures of such
locomotives to include on this page:
HP Olean 7 in 2005 is a typical example:
On the mainline in Java, two (very
similar) classes used this system, this was D1503 on a Tegal to
Pekalongan train in 1976. These locomotives frequently worked as
0-6-2s with the rear rods off.
Locomotives with extra Lateral Movement of Certain Axles
These are not included in Wiener's work and may not
strictly be considered a form of articulation. However, since they competed directly
with the types listed above, it is worth including them here. BMAG
(formerly Schwartzkopff) produced a series of 0-10-0T in which there was
extra lateral movement possible in the outer axles. The drive was taken on
the central axle which was flangeless and this meant that the first,
second, fourth and fifth axles could follow a curve while the third stayed
aligned with the cylinders. The second, fourth and fifth axles have extra
side play of about an inch with extended crankpins and naturally there had to be extra flexibility
in the way the rods were connected. The diagram below by Roger West was first published in the
Industrial Railway Record in 1975.
feature of this design is a 'dummy' 6th axle which was intended to ensure
things got back to normal quickly on the straight, but was left out of
later designs. Both inside and outside frame varieties survive in Java,
the first picture shows Sragi 7 in 2002:
All inside frame locomotives of this type in the
sugar mills are out of service, but the Cepu Forest Railway has three of
them, used on occasional charter trains these days, this picture was taken
during such an event in 2002.