[GreenKeys] WU 1-A and Iron Horse pics

[Jim Haynes]

Your Iron Horse seems to have an unusual attachment - that thing that the
tape passes through ahead of the punch block.  I'm guessing it is a hand-
operated punch to nibble the edge of the tape.  The reason for nibbling
is to let the tape-out pin in the reader operate, thus stopping the 
reader.  But I had never seen one of those on an Iron Horse before.