Based on my experience using trains in Tokyo, people are doing one three things:

• Use their phone
• Read printed material
• Falling/is asleep

Based on visual monitoring, I believe 6 out of every 7 people are using their phones. The remaining one is either reading a book (yes folks people are still reading printed material), or partially both.  You can see this from the above picture when looking at the seven people sitting on the bench seat.  Always amazed at how people can quickly wake up and get off at a stamp.

The only time this figure of reading printed material changes is when the train is at literally crush capacity, the books are put away.  Surprisingly a few people still manage to maintain reading their phones.  The need to hang on while the train in motion no longer applies as you are packed in like sardines, to everyone.  

And phone of choice…? Appears to be a smart phone.  Too hard to distinguish between different brands, as there are so many. Although I acknowledge to seeing a rather large number of flip phones – ah technology.