Class I1-44 (Locobase 7090) 
Data from NC&StL 1 - 1921 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.
Drury (1993) makes no mention of this Twelve-wheeler trio, shown here in its earlier saturated-steam configuration. The long wheelbase and the long stroke typical of the arrangement shows in these as well. Clearly, the railroad thought enough of them to put in some flues and the result is described in Locobase 7089.
These two were scrapped in September 1926 (852) and August 1932 (851).
Class I1-44 - superheated (Locobase 7089)
Data from NC&StL 1 - 1921 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.
Drury (1993) makes no mention of this Twelve-wheeler trio, shown here in its superheated form and in Locobase 7090 in its earlier saturated-steam configuration. When the engine was superheated, it lost some heating surface area as often happened, but gained 26 sq ft of arch tubes as part of its firebox heating surface.
Perhaps surprisingly, given the effort made to modernize the design, 850 was scrapped in November 1927, only a year after 851.