The 5th era is the streamliners and lasted to about 1980.

Beginning in the 30s, serious efforts were made to remove the deadweight of the massive heavyweights for reasons of both initial and operating economy. The new streamliners were built of steel (by Pullman-Standard and/or American Car & Foundry) or aluminum and stainless steel (Budd) and often came in fancy choler schemes.

It was an era that ushered in dome cars and other new variants of first class travel. Pullman was forced to divest in antitrust action so ownership and operation of cars passed to the railroads and Pullman became solely a builder.

This era lasted a very long time as the demise of intercity passenger travel in the 60s killed the further development of new passenger cars for 2 decades.

A view of Lehigh Valley Black Diamond express streamliner in 1939.