Identifying individuals in the A.J. Russell Promontory Champagne photograph

From: "Sheldon Walton" sheldonwalton@yahoo.com
Subject: Joining of the Rails, May 10, 1869, Promontory, Utah

Joining of the Rails, May 10, 1869, Promontory, Utah

The Picture of the two trains facing each other, with all the men around.

Any way of identifying who's who?