Re: Question, type of coupler, DGO, 1905-1923

Yes, the coupler in the photo is a miller.
Miller hooks were very common on PASSENGER CARS ONLY in the 19th century, reportedly found on up to 85% of the passenger cars in use. The most significant hold out was the Pennsylvania RR.
Millers were not designed for train crew safety, they were designed to improve passenger safety.
Platforms on wooden passenger cars were not part of the carbody, but were instead cantilevered off the end of the car. In an accident the platforms collapsed, and the carbodies telescoped. Miller couplers (or hooks) were only a part of the miller platform system. The platform was notched, and trussed in a way that was supposed to prevent collapse in an accident, and prevent telescoping. The hooks were very long, and bolted to the carbody, between the end beam and the bolster. They were only good in tension, and depended on buffers for compression forces. This also meant that the train was rigidly coupled, providing a better ride.
Millers all had a pocket (very visible in the photo) for link and pin couplers. Millers were never installed on locomotives, but a casting to bear on the buffers was.
In addition to the hook at Sumpter, there is a reportedly a coupler on a one end of a business car in Rienlander (sp?) WS, and one end of a Boston and Revere Beach car in a private collection.
Many of the former SP ng and V&T passenger cars have much of the miller equipment intact, with only the head of the miller hook replaced with a janey casting, and a second spring installed to center the coupler (CSRM has plans for this conversion). When we restored SP 1010, we were able to locate examples of all the parts, but the hook itself. We discovered that narrow gauge miller was smaller than standard gauge examples.
Randy Hees
SPCRR