COX Catalogs
1972 COX
1974 GO COX!
1975 COX '75
1976 COX Power '76
1977 The New Age of COX
1978 Leisure Dynamics (Canada)

1977 The New Age of COX Catalog

The New Age of COX catalog was published to promote 1977 product .  It appears this new age was not to favor HO-scale model trains to the extent they enjoyed in previous years. 
The 1977 COX catalog contains 64 pages and HO-scale model trains take up pages 52-59.  Five train sets are featured, followed by a pair of pages covering Big Pine Lumber and Dockside accessories.  Finally, the last two pages display a very limited selection of rolling stock and even more limited locomotive selection.  The Championship Train GP9 is the only locomotive shown as a separately sold item in 1977.
To my knowlege, this is the final COX catalog in America to feature HO-scale model trains.  The line does surface again in 1978 and 1979 in Canadian Leisure Dynamics catalogs.