Stronger, lighter materials allowed larger cars to be operated. More freight could be hauled in one car for less cost. Chachinggg...
Nope to this one. Cars were still being built out of simple, plain-carbon steel. Certainly design had improved, with far smaller center sills once the ARA design became standard for all-steel box cars. Even the slightly higher strength steels used in the 1960s did not really change dimensions of structural parts. And "lighter?" Nope.
Anthony Thompson Dept. of Materials Science & Engineering University of California, Berkeley thompsonmarytony@...