4-8-4 Locomotive Frame Casting in Half Inch

Jump to: navigation, search

by Mr. George H. Grieb

The Modelmaker, Volume 9, Number 8, August 1932

Having had some experience building a 1/2 inch scale Pacific locomotive bed from castings, and parts cut out by hand from cold rolled steel, I decided for my next model to use a one piece frame casting.

The casting shown in the photo is of a general design for a 4-8-4 type locomotive. Such a casting eliminates a great deal of filing and fitting. Instead of about nine different castings to machine with about fifteen or more machine surfaces to be finished, I have one casting with only the two pump bracket faces, the four boiler and firebox support lugs, four pedestal openings, cylinder seat, and pedestal binder seats to machine. Furthermore the casting insures correct alignment of the parts and a strong back-bone for the model.

The casting rough weighs about 10 pounds. It is 31-5/8 inch in overall length and measures 3-13/32 inches between pedestal opening center lines. It is made of a good quality brass. The six frame filling pieces are cast in place and have openings cored in them for the spring equalizers. The eight brake hanger supports are also cast as part of the frame. The coupler and drawbar pockets are cored out. The coupler pocket having an extended floor as in the latest designs.

With the idea in mind of using ball on roller bearings in the driving box journals of my model the frame casting was provided with sufficient metal on the pedestal faces to permit machining out the pedestal opening for such a bearing.

The frame is suitable for use in building models of the Timken Locomotive, the Chicago, Rock Island and Pacific class R67b, the Delaware, Lackawanna and Western (Pocono) class Q, and Q2, and the Denver and Rio Grande Western class M-64. This was the reason for the general design as I hope some day to build models of all these locomotives using this frame to start with.