During the first half of the 20th Century, three artistic movements affected the aesthetics of design. First was Art Nouveau, a very fluid style. It thrived until the early 1920s. Next was Art Deco, a curious blend of modern, Neo Egyptian and Neo-Babylonian motifs. It was the rage from the early 1920s until the 1940s. In the 1930s, the Streamline style emerged. It was notable for its sleek lines and feeling of motion.
Three of the best examples of Art Deco are the Chrysler Building, Radio City and Rockefeller Center in New York City.
Streamline styles are found in the M10,000 and Burlington Zephyr.
The GG1 is a blend of Art Deco and Streamline. F and E cab units are mostly Streamline. FA and PA cab units are mostly Streamline with a hint of Deco.
Popular art movements had great influence in their day. They did much to affect the design of the First Generation Diesel locomotives and the steam Streamliners such as the Dreyfus and Vanderbilt. Architecture, jewelry and even clothing styles were also touched by the art of the day.
Note that just because a new artistic movement takes hold, the previous ones do not fade away. The old tends to abide alongside the new, especially when it comes to buildings and trains. Look at older Main Streets and you will see storefronts bearing the motifs of the era in which they were erected. Art Deco and Streamline stand alongside subsequent building styles. There may be a few changes over the years, but the essential motif is still perceptible. Consider this when designing your miniature towns and streets.
The majority of houses and other structures in a town will be those popular when the town was founded. Newer style homes and buildings are erected among them. So it is that one can find a neighborhood that has structures from the Revolutionary War era to the present standing side by side. One can very well find a 1950s Ranch type home tucked in between a Colonial split-level home and a current style frame house. The only settlements where all homes the same era and style are planned developments rather than towns and cities.
If you want to see Art Dec oand Streamline, look at advertising art of the 1920s to the 1940s. Advertising likes to use current motifs, so you get a good idea of the guiding aesthetic in he time they were drawn.