The railroad in question is the Dahuichang Limestone Railroad, a short distance outside Beijing. It, like most narrow gauge in China, uses link and pin couplers. The cars a loaded inside a tunnel then at the other end, the engine cuts off and does a flying switch so the cars roll down to the rotary dumper. These cars have no air and workers use steel pins they put into the wheel spokes to let the sliding wheels stop the cars.
There are always two trains running, with meets at either end. The maintenance on these engines is minimal so when they're down they need extra power to cover.
And I beg to differ on the whistle sounds. These engines have beautifully sounding whistles, although seldom used (only one grade crossing on the line). Most signalling on Chinese railroads is done with an air horn, which does often squeal and which I hate. When you are out in the countryside, the steam whistle will be occasionally used and most of the ones I have heard on the JiTong and Hechi lines have been great. Like any whistle, valve problems,the ports for steam around the base of the bell and the positioning of the bell itself will affect the sound.
The first one I bought on JiTong cost about $125 last year. By this year, it cost around $200. And I still had to buy a suitcase to carry it home in plus drag up and down stairs at RR stations and hotels plus shlepping it around on taxis and airports and explaining it to customs and security. I haven't had the opportunity to try them yet but the casting process leaves much to be desired so I will probably have to do some work to clean excess flash from the steam ports.
You can see more of these engines on my website.
