Re: Freight Car Trucks - when?


Richard Hendrickson
 

On Feb 18, 2006, at 2:24 PM, Jim Betz wrote:

  I thought I had a handle on this and then I started asking myself
some questions and realized I didn't really know enough.
  I know stuff like when certain truck styles were banned in
interchange (thanks to people like Guy W.).  But I was trying to
answer stuff like the following and not only don't know but don't
know how to find out ...

  When were the various truck types introduced?  Arch Bar,
Andrews, Bettendorf, Bettendorf T-section, Barber S-2, etc.
  And the other side of the coin ... when did they go out of
favor (stop being common)?
  How long after the all-cast trucks were introduced were they
essentially used on all new cars being built?
  Why was there a Bettendorf and also a T-section Bettendorf?
The basic arch bar design was introduced in the mid-19th century and
had become almost universal by the 1870s (see John H. White, Jr. The
American Railroad Freight Car). Pressed steel trucks such as the Fox
and Wright designs began to appear in the 1890s and had brief
popularity around the turn of the century but soon became out of favor
owing to problems with their pedestal journal boxes binding in the side
frames. Cast steel designs with separate, bolted-in journal boxes such
as the Andrews and Vulcan trucks dated from around the turn of the
century and were used in increasing numbers before WW I, though arch
bar trucks were still common.

The first trucks with the journal boxes cast integral with the side
frames were T-section Bettendorfs, which also first appeared around the
turn of the century and were so named because they were developed by
the Bettendorf Co. of Bettendorf, IA. T section trucks, whether
Bettendorfs with integral journal boxes or Andrews and Vulcan, were
prone to side frame cracking, especially when loaded heavily, so
U-section side frames began to replace them before WW I (e.g., the USRA
Andrews trucks applied to USRA freight cars in 1818-1920). After the
war, the Pennsylvania RR introduced a U-section truck with integral
journal boxes which, with minor variations, was adopted as a standard
design by the American Railway Association (designated the Type Y).
The basic principles of this design were then incorporated in a large
number of somewhat different trucks by different manufacturers, all of
which conformed to ARA specifications and had U-section side frames and
spring planks and can be considered under the generic label of ARA
trucks. These were sometimes loosely called "Bettendorf" trucks by
railroad workers (though not by railroad mechanical engineers) because
they incorporated the Bettendorf principle of journal boxes cast
integral with the side frames, a bad habit that was picked up in late
years by modelers and model manufacturers; hence the confusion about
the Bettendorf name. The Bettendorf company itself manufactured trucks
of numerous designs (including the T-section truck, which was still
being made in the 1920s, and a swing-motion caboose truck which was
widely used from the mid-1920s onward). However, Bettendorf became an
increasingly minor player in the freight car truck market and ceased to
manufacture trucks ca. 1942.

Arch bar trucks, though still manufactured until the late 1920s, were
largely replaced after World War I by U-section Andrews and Vulcan and,
increasingly in the 1920s, by ARA trucks with one piece side frames.
Among the various ARA 1920s designs were Dalman trucks, which had more
and softer springs for improved riding qualities. Many trucks were
also equipped with lateral motion devices to improve riding qualities,
the most popular of which was the Barber design of the Standard Car
Truck Co. All of the major truck manufacturers applied these features
to their trucks under license agreements.

Experiments in the 1920s showed that snubbers (actually primitive
friction shock absorbers) also improved riding qualities, and starting
ca. 1930 freight car trucks were introduced which incorporated built-in
snubbers. The first of these to be widely used was the National B-1,
which also eliminated the spring plank in favor of a precision-machined
sliding joint between the side frames and bolster. The latter
principle was also developed for ARA trucks (which became AAR trucks in
1934 when the ARA was reconstituted as the Association of American
Railroads) by a consortium of truck manufacturers, resulting in AAR
self-aligning spring-plankless trucks. Another improvement made in the
ARA/AAR design at about the same time was the "double truss" side frame
which had box-section instead of U-section lower chords. In the mid
1930s the Standard Car Truck Co. introduced its Barber Stabilized S-1
AAR truck with built-in friction snubbers, and this soon evolved into
the Barber S-2, which was applied to growing numbers of freight cars in
the early 1940s. A similar design was developed by American Steel
Foundries which, though its introduction was delayed by World War II,
began to appear ca. 1944; this was the "Ride Control" A-3 truck. After
World War II, all the truck manufacturers developed proprietary designs
with built-in snubbers (e.g., the National C-1), but the Barber S-2 and
ASF A-3 were by far the most popular and are still being built in large
numbers today as roller bearing trucks.

  So has any one written this up some where?  Is it online or
in some book I need to study? 
Most of it is covered in my copiously illustrated monograph on freight
car trucks in Railway Prototype Cyclopedia, Vol. 4.

Richard Hendrickson


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