Thomas Curtis Clarke,
The American Railway: Its Construction…
“ It can also be unlocked by the rod shown extending to the side of the car, and the locking device can be set not to couple, to facilitate switching and yard work. The mechanical principles of this coupler are a great and important improvement upon any form of link-and-pin coupler; and the coupler question has now come to this point: A type of coupler has been selected by a technical body representing most of the railroads of the United States. It is general enough to avoid the evils of a patent monopoly. ”
