These keys were found at an estate sale in a toolbox belonging to someone that worked for the railroad for 40 years. We were able to identify two brass switch keys (not pictured) that were also found with these keys but we cannot figure out what these keys are. Can someone help identify these keys? The round black key has an "x" in the right corner and the stem moves back and forth (the first two pictures are the same key); there is also a hole on each side of the key. The other keys' markings are more visible in the pictures. Thanks!