The USRA Gondolas in 1918 H&B Lots 5176, 5180, 5183 had pin & chains for both side & end doors.  Alternative mechanisms, panels and other details were made for the SSC 1932 USRA alternate.  I haven't yet run into the General Arrangement drawings, they are most likely there as well.  The butt plate & hinges, pin & chains, brake details and other drawings have been scanned. 

The door mechanism drawings for drop bottom gons usually are vendor drawings, not manufacturer drawings.  While a general arrangement drawing will show some information, the URE (or other vendor) drawings are referenced, though rarely copied for such.

At 08:53 AM 4/14/2020, David via groups.io wrote:

The original USRA gons used a windup shaft mechanism for the doors. Wine door locks were used on a number of copies built in the 1920s, and sometimes retrofitted to the originals.

David Thompson

Bob Webber