I went to look at some books to see if there were any things I can use or apply.
“The squareness … helped exaggerate the roundness of the … through contrast.” I can apply this to my train settings whereby the organic(or relatively round head forms) contrast with the straight horizontal and vertical lines found in the train environment.
Here, the artist groups the objects together, such at the bar stools in the relatively central area. The people are silhouettes, some parts standing out from the background and other parts blending in with the surroundings. I like how there seems to be a light source, the right of the sketch seems to be a full length window or entrance, while the left bar area is darker.
Here, it shows how the mood of the painting can be vastly different all due to the addition of a light source. Left, the light source from a doorway makes the painting more lively. It draws our attention to the ballerina on the left that is brightened up by it. I can take note of this by adding a bright/light area to my train settings to engage the audience.
The full length window allows light into the cafe scene. The highlighted edges of the chair or table tops are exaggerated. This creates an illusion of light streaming into the cafe. I can take note of this and apply this to the top of the heads of the commuters on the trains, assuming the brightest light source is the ceiling lights.