Premise: The Chattenden and Upnor Railway (later known as the Lodge Hill and Upnor Railway) was a narrow gauge railway serving the military barracks and depot at Upnor and associated munitions and training depots. It was built in 1873 as a gauge railway, converted to narrow gauge around 1885, and continued in use until 1961.
Hypothesis: The Chattenden and Upnor railway stopped being in use exactly 40 years ago.