Gilbert soon moved the company from Chicago to New Haven, Connecticut, and re-designed parts of the product line. The initial changes included substitution of the 'slot & tab' couplers with link and pin semi-automatic ones on the higher priced 10" freight cars and steam engine tenders. Three significantly detailed & overall scale length O gauge steam engines were introduced in the 1938 catalog: Atlantic (4-4-2), Pacific (4-6-2-) and an 0-6-0 switcher. The years 1938 through 1941 saw the production of Gilbert's "Tru Model" 3/16" O gauge trains. The engines offered in this line were fairly accurate scale replicas of the locomotives they were modeled after. A Reading Lines Atlantic, Pennsylvania K5 Pacific, a NYC Hudson, a B&O streamlined steamer (Royal Blue), a UP Northern (4-8-4) and an NKP 0-8-0 Switcher. This line would later become the postwar 3/16" scale or S gauge line with two rail tracks. Also, its HO product line was introduced in the 1938 catalog. The design of the initial version of the HO track was significantly different from that of typical electric trains: the rails were mounted on lithographed roadbed.