Good find, Bruce. I had forgotten all about the older thread you linked; I did not apparently save that particular photograph. As expected the very-unique combine was the key.
Is there a possibility that the Mason (the centennial engine, apparently) is in fact the same engine as we mentioned above? The Grafton Centre changed gauges in the late 1880's which would presumably have rendered this engine surplus unless it were also regauged. In particular does anyone know where the Hoosac Tunnel and Wilmington engine came from? At the very least I expect it was also one of the former New York & Manhattan Beach engines, and possibly the same one since this road was still under construction when the Grafton Centre changed gauges and the two roads were physically not all that far apart. Be interested if anyone knows one way or the other. Those Masons got around quite a bit.