The couplers are similar to the ones used on Apache Powder Co. in Arizona. We have a set that came with Apache Poweder no. 10, a 5 ton model FL Plymouth at the Nevada County Narrow Gauge Railroad Museum in Nevada City, CA.
The videos of Porter no. 3 running in Japan sure brought back memories of 50 years ago. That 2-6-0 was the first loco I was fireman on at the Camino, Cable & Northern RR at Camino, CA in the fall of 1964. I had ridden behind her at Hal Wilmunder's Antelope and Western RR at Roseville, CA in the early 1960's. He moved her to his new CC&N operation in 1964.
She was a good 18 ton loco and managed to get three cars up the 1/4 plus mile, 3-1/2% grade. In the late 1960's she received a new welded boiler and was sold in 1974 to the Huckleberry RR. There she was found to be to small for their heavy trains. A private party bought her and later she went to Japan.