Re 520 or 621

["Trevor Gibbs" <xdford@one.net.au>]

 >Have you ever thought of converting 520 to standard gauge.  I was told,
>and you may check this , that 520 was built able to be gauge convertable.

All SAR Engines and Rollingstock post Webb ( 500, 600 and 700) were built
to be readily gauge convertible...

The wheels in all stock were slightly "dished" or cupped shape so that by
reversing the wheels relative to the axle and tyres, the gauge could be
widened or narrowed. The difference of BG to SG is 6 and 1/2 inches so the
offset need only be 1 and 7/8" on either side of the axle, virtually next
to nothing in Railway terms. All steam engines had two brake hangar
positions but of course it was never required.

I remember reading in an old RT magazine that 400 class garratts were
supplied with wider gauge axles and had three brake hangar positions. 

Even the 600's, 700's and 830's supplied to the SG had cupped wheels... I
know because I worked underneath these on both Broad and Standard Gauges as
an electrician... 700 BG engines were a real tight squeeze whereas 700 SG
engines seemed to have a bit more room in the right places replacing
brushes etc.

The problem from what I have read in the past appears to be with NR wanting
to look like a "modern rail system" and steam engine compatibility is one
issue. At least the Victor Harbour line is intact for generations to see. 
BTW 520's are a more economical engine than 620's on a load/fuel consumed
basis ( Source "500", Fluck, Stewien, Thomas)

Cheers


Trevor