Not sure if this qualifies as a go-with but found this while digging around a threadless pole location on a former 1850's era rail line in eastern Ontario. It is about an inch in diameter and made of copper. It's in pretty good shape as it was shallowly buried in a layer of cinder rich soil underlain by gravelly soil. I thought that it might be a baggage tag. The pictures I've seen on the net of baggage tags usually had the name of the railway but this is just a plain number. The rail line started out as the Brockville and Ottawa Railway and was taken over by the CPR in 1881 as the first leg of their transcontinental line.