The C-25 frame.




The frame for the C-25 was based on Al Armitage's Gazette drawing, on the erection card for the Silverton Northern no. 34 in The Rainbow Route, and on a photo of US Potash no. 3 supplied by the Railway and Locomotive Historical Society.

The design is dimensionally accurate, while simplifying the prototype's design some in the interest of easing production.  The gibs in the axle box pedestals have been incorporated into the frame, and the rear extension is cut from the same thickness metal as the main frames.  The pedestal binders are simple bar stock.

After much consultation with the readers of the live steamers and HO scratchbuilders discussion lists, I decided to equalize the running gear, but not spring it.  This decision was based on the desire to maintain positive contact between the wheels and track at all times (which the equalization will do), and the difficulty of getting scaled-down springs to work properly.  Many modelers have reported excellent results equalizing without springing, so I'm going to give it a try, too.

The photo included here was of the test cut of the frame, without rigging. The springs are 1:24 scale brass castings from Precision Scale, and will not be used on the final version.  Cylinders are from Roundhouse Engineering; they will be covered with shrouds to bring them to accurate scale size.

References:

  1. Mike Sharman.  Flexichas.  (1982.  Oakwood Press. SBN 86093 072 6)
  2. Jerry Howell.  "Equalizers for steam locomotives."  In Model Railroader, Sept. 1972, p. 62.
  3. Kenneth F. McCall.  "Principles in the Design of Locomotive Spring Rigging".  In Railway Mechanical Engineer, Sept. 1933, p. ??.

© copyright 1997, 1998 by: Vance R. Bass .
Back to Drawings for Small-Scale Live Steamers.

Updated on 1 May, 1998.