Nigel,
Went back to the Index of Magazines and just used the search term “dumper” rather than the “rotary dumper” I used the first time, with the result I found a few more articles that may be relevant.
Bob
Car dumper, Model Railroader, June 1945, page 251
( CAR, DUMPER, ORE, “WILEY, CHARLES F.”, MR )
Rotary car dumper,
Railroad Model Craftsman, December 1979, page 85,
( “BUCKLEW, ROBERT”, DRAWING, DUMPER, ROTARY, RMC )
Adding an operating gravel dumper, Model Railroader, April 1991, page 68,
Article also published in HO Railroad From Start to Finish, page 18
( BEGINNER, DUMPER, GRAVEL, “KELLY, JIM”, STRUCTURE, MR )
Coal Dumpers - Part 1: An Overview And A Look At The Port Reading Facility,
Model Railroading, April 1993, page 44 ( COAL, DUMPER, “ROSEMAN, VIC”, UNLOAD, MRG )
Coal Dumpers - Part 2: The Dumper At Vestal, Model Railroading, May 1993 page 59 ( COAL, DUMPER, “ROSEMAN, VIC”, UNLOAD, MRG )
Adding an operating gravel dumper, HO Railroad From Start to Finish, page 18, Article also published in Model Railroader, April 1991, page 68
( BEGINNER, DUMPER, GRAVEL, “KELLY, JIM”, STRUCTURE )
Simple Modeling Projects: Car Dumps, Model Railroading, September 1997, page 21, ( DUMPER, HOPPER, “INGBRETSEN, ROGER”, LOADING, FREIGHTCAR, MRG )
Rotary dumper, Mainline Modeler, June 2001, page 72, photos of dumper at Silver Bow, Montana ( DUMPER, INDUSTRY, PHOTO, “WAITE, THORNTON”, MM )