Courtesy Bruce C. Cooper Collection.
Dick Dawson comments* that "When I was writing the section on couplers,
draft gears and hydraulic
cushioning devices for the 1997
Car & Locomotive Cyclopedia, I came across a
reference to a manufacturer who advertised in the early 20th century the
availability of 119 different designs of coupler knuckles. This reflected a
key problem with the "standard" knuckle couplers then in use.
When the Master Car Builders Association adopted in 1888 the coupling face
contour lines of the 1879 Janney coupler patent, they ensured that all
couplers built to the MCB standard would be able to couple with each other.
They did not, however, standardize the dimensions of the various parts of
the coupler - the knuckle, lock, interior of the coupler head, etc.
Consequently, all cars equipped with MCB couplers could operate together,
but maintenance of those cars in interchange became a real problem. When a
car showed up at a repair track with a defective knuckle or coupler that the
shop did not stock, the shop had two undesirable options - send the car home
for repairs or wait for compatible parts to be shipped to the car.
Consequently, the MCB Coupler Committee asked the coupler manufacturers in
1911 to cooperate with the Committee in the development of a coupler, all of
whose parts would be interchangeable regardless of manufacturer. After
reviewing nine submitted coupler designs, the MCB selected two, submitted by
American Steel Foundries and National Malleable Castings, for further
development. The revised National design, the Type D, was adopted as the
new standard coupler in 1916. A licensing arrangement was developed by the
coupler manufacturers under which all had access to each other's patents and
all could produce the standard coupler and its parts. While the D coupler
provided a number of benefits relative to prior couplers, such as greater
strength, its primary benefit was the complete interchangeability of all
Further development led to a coupler which offered significant advantages
relative to the Type D but whose parts could not be made interchangeable
with those of the D. This became the Type E coupler which was adopted by
the ARA (successor to the MCB and predecessor of the AAR) in 1930 and
advanced to Standard in 1932. 74 years later, the Type E is still the most
widely used coupler. Today's E couplers are improved in many respects, such
as the use of higher grade steel, but the parts are still interchangeable
with those of a 1930 coupler. Passenger cars now use interlocking couplers
based on the AAR Type H and rotary dump cars use Type F interlocking
couplers, but the vast majority of freight cars built today are equipped
with Type E couplers with shank lengths appropriate to the car
*[from the R&LHS Newsgroup]
Eli H. Janney's 1873 U.S. Patent #138,405 for "Improvement of Car Couplings."