My wife and I have a small 500' right-of-way, 7-1/2 gauge, railroad in Northern New Jersey. I have a 2-6-0 Mogul, but most of our running is done using an 0-4-0 gasser. (easy for the kids to run) One of my neighbors had wanted to bring his 3 yr. old granddaughter for a ride for some time, but something always got in the way. Finally, one recent Sunday we were running for our own grandchildren, and he heard the train. He brought her over to ride the train, but she was very very shy, and her parents even had a difficult time convincing her to take a ride. She got on the train with her grandfather, and we left the station. My right-of-way has a 2 % upgrade as we go over a 65' long bridge and re approach the station)
The ride was going fine until we cleared the bridge, then the coupler between the engine and the first car of the train failed. There was a slight jolt when the safety chain took up the slack, and we were able to proceed to the station without further incident. Bottom line of the story is that a serious problem was avoided by the use of a simple, and sometimes overlooked safety device. (if the cars had gotten loose, they probably would have gone over a 5' embankment at a fairly high speed) The coupler in use was made of cast aluminum, it is commercially available, and came with the engine. Needless to say I replaced it with a cast iron coupler, and will never again use an aluminum coupler.
Being in Northern New Jersey we have our share of ups and downs, but no matter how flat your right-of-way may be the use of safety chains is imperative !!!! Save some heartache, they only take a couple of seconds to hook up, and provide cheap insurance when running.