It is track chisel (cut devil, rail splitter, etc). Never intended to be used as a hot set. Never even heard of a hot set that is sharp. Most "set" tools are for refining internal corners in hot forge work, or in a pinch, as a small flatter.
These are common to find around most places that had track running through them, at least on the east coast. I have seen them from several different manufacturers....warwood, woodings Verona are two commonly found in my area.
