Inside a metro train car, a doorway leads to an adjacent, crowded car

Inside a metro train car, a doorway leads to an adjacent, crowded car. People are visible in the doorway, with some holding onto handrails. A young boy in a red and black jacket is peeking into the other car, leaning on the panel next to the door. An adult is taking a picture with their phone, and a few other people are visible in the foreground. The train car's interior is white with a bright, rectangular light fixture.