Today's question is about a Western Railroad Supply rail drill. I cannot figure out how it is supposed to clamp to the rail. As seen in this photo there is one piece that spans the rail. It is hinged to a short filler piece that is hinged to the drill itself. Apparently that short filler piece is designed to rotate upward thus drawing the drill up to the rail. What I cannot figure out is how the piece rotates and what holds it in place.

Anyone out there use one of these and know how the clamping mechanism works?

It doesn't clamp. The hook just gives a restraint so that when you turn the crank to advance the spindle you're only cranking and not trying to push like you would with a hand-held drill. Those Westerns are very simple drills with no way to set drill height. In the second pick you can see the drill set up on bars as a guide.

I have figured it out. I have one alteration to make and this drill will work as originally intended.

Thanks.