Miller's Platform & Couplers
Miller Couplers were used by many railroads on passenger equipment – and other high speed equipment such as fruit and silk cars used in passenger trains or at passenger train speeds. (Central Pacific, Denver & Rio Grande, and Northern Pacific had such cars, and maybe others did.) Note cars with Miller Hook couplers also had platforms, generally Miller patented platforms.
They were common between the 1860s and the 1890s, with a few applications lasting longer (such as the insular Boston Revere Beach & Lynn).
There was a slot in the face of the coupler that could accept a link.
Check out the following web pages:
discussion on Miller hooks, with particular reference to Central Pacific fruit cars. Note links, including to Miller drawings from the 1884/1888 Car Builder's Dictionary (note 1888 was a reprint of 1884 – and the 1888 issue has itself been reprinted in the 1970s.)
The Development of the Semiautomatic Freight-Car Coupler, 1863-1893
Charles H. Clark
Technology and Culture, Vol. 13, No. 2 (Apr., 1972), pp. 170-208
This discussion also gives links for several Janney coupler patents - note you [may] need to download the Patent Office graphic viewer – free – to look at the images.
Restored cars with Miller couplers include:
Virginia & Truckee coach #4, Nevada State Railroad Museum
Milwaukee Lake Shore & Western coach #63, Mid-Continent Railway Museum
Southern Pacific combine #1010 (narrow gauge), society for the Preservation of Carter Railroad Resources (SPCRR), Ardenwood Regional Park, Fremont, California.
That should get you started.
[from the R&LHS Newsgroup.]