USRA Designs

USRA Mikado Steam Engine






Appliances - Hodges Trailing Trucks


The USRA used the three major US locomotive builders for building its locomotives - Baldwin, Alco and Lima. For the most part the builders had the freedom to select the materials and parts the builder conventionally suppllied. These did, however, have to meet the material and dimensional standards of the USRA guides.


The USRA, however, specified specific suppliers for many of the locomotive's appliances. This was the case for the locomotive's trailing truck. At the time, the two principle competing trailing truck designs were the Hodges manufactured by Baldwin and the Cole-Scoville manufactured by ALCO and consider at the time, the better of the two. A third design, the Delta type, developed in 1916 by Commonwealth Steel Company utilizing a one-piece cast frame exhibited unstable lateral centering and as such was not included by the USRA. The design flaws in the Delta were corrected in 1921, and it became very popular in engines that imitated the USRA's Mikado design in latter years.


The USRA Mikado steam locomotive specifications called for Cole Trailing Truck to use on Heavy USRA Mikado and Hodges Trailing truck on the Light Mikdo.


(Source:Uncle Sam's locomotives: the USRA and the nation's railroads; Eugene L. Huddleston; 2002 )


Hodges Trailing Truck


The Hodges Trailing truck was invented and patented by William S. Hodges on September 13, 1910 and assigned to the Baldwin Locomotive Works. The design was provide "certain improvements in rear swing of trailing trucks of locomotive, and one object of the invention is to so construct the truck that it can be either allowed to swing or be rigidly connected to the main frame of the locomotive as desired and a further object of the the invention is to provide means whereby the truck can swing without affecting the position of the springs in respect to the main frame." (Source: United States Patent Office, Patent #970,333) A copy of the patent can be seen here.


Baldwin improved on the design, replacing many of the bolted together components with casting so that by the time they were used in the USRA Locomotives, they were starting to look modern.

(click on picture for a larger view)

Steam Locomtive Air Brakes Steam Locomtive Air Brakes Steam Locomtive Air Brakes

Source: 1922 Locomotive Cyclopedia of American Practice

Source: 1922 Locomotive Cyclopedia of American Practice

Source: 1922 Locomotive Cyclopedia of American Practice