During Summer, 1942 Gilbert (as were many manufacturing companies) was compelled by Federal wartime restrictions to cease manufacturing (and even servicing!) its electric train and other metal consumer products. It did not again publish American Flyer catalogs until 1946. The manufacturing hiatus offered the company the opportunity to further differentiate the products from those of the market leaders (by sales volume) Marx and Lionel. By Summer, 1945 it was able to resume limited manufacturing of the 3/16s scale O gauge trains. While it did so, the same sized products were re-engineered to run on much more realistic two rail (with a "T" profile rail) track. The fine detail of the diecast engines, tenders and cars that had debuted in the '39 catalog reappeared. The engines and tenders continued to be made of diecast metal, but the cars' bodies were made out of plastic. Two pages of the spectacular 1946 catalog emphasize the running advantages of the lighter cars. Ironically, they soon realized that they had to add weight. Metal car bottoms & chassis were necessary to prevent the too-light cars from tipping over. The 'link & pin' automatic couplers that had been introduced on the 3/16s O products were reduced in size, with plastic replacing the sintered metal of the originals. They too, later had metal weights added because they would fail to descend to the locking position needed for cars to couple. The chugging mechanisms of the premium O gauge tenders were redesigned to also generate smoke, which was conveyed to the engines' smokestacks via a black rubber tube that protruded out of the rear of the cab so that it could connect to the front of the tender.