Dennis, if it were a Bishop competitor it would have a notch cut in the end, to center the side of the link as you raised it. (It would also very likely be two-handed, perhaps like a scythe, to make it easier to control the extended blade from 'outside'...)

If I'm not mistaken, the outside end is worn considerably. That would jibe with the idea that it's to clean the tops of the ties, under the rail. But would that give it as much wear as I see?

This tool is called a trowel and was used to lift joints on bolted rail. The joint would be lifted just above level and ballast stones would be placed on the trowel and slid under the ties. The trowel would be yanked out leaving the stones behind. Sectionmen would quickly become skilled at placing the right amount of stone on the trowel and tapering out the lift each way as they got further from the low spot. I have seen this done for miles on the CN Thorndale Sub. in the 1980's. The foreman would have a Rule 42 permit on the track and trains would call for permission to go through. They only had to knock down the jacks and let the train go with no time lost clearing on rail tampers etc. As soon as the train cleared they were back at it, so productivity wasn't as bad as it seems.It all seems archaic now.