Railroad Rim

[Roller]

A partial collar strike sometimes called a railroad wheel rim or a railroad rim

a totally jammed collar will result in a broad struck coin as no collar was present to hold the metal in place
but if the collar were half jammed and half holding the blank disk that will become a struck coin...

"...In this position , if a blank is fed into the collar, only part of that blank ( the lower part ), will be contained by the collar , while the upper part of the blank will not be controlled by it. When the blank is struck, the lower part will be formed into the correct diameter because of the partial presence of that collar. the upper part of the blank will be free to spread in a manner of a broadstruck coin. Both the obverse and the reverse designs will be in their essentially normal shapes."
" The edge of this coin will have the unusual shape of two distinct diameters. If viewed edgewise it will appear to be very much like the conventional shape of a railroad wheel with its flange which permits it to remain on the rials of the railroad." THE ERROR COIN ENCYCLOPEDIA 4TH EDITION. Page 324 by Arnold Margolis and Fred Weinberg.

Good job John. Meanwhile, I happen to have a finned rim example set aside yesterday.