I used to commute nearly an hour each way on the tube in London, and read endlessly. Until someone asked me about the books I'd read lately and in could barely recall then story lines. Yes at the time I was engaged and was enjoying the story and act of reading, but it just didn't go in to my mind in the same way that reading at home or on the beach does.

So I stopped reading and started cycling. Much better use of my time, and I was forced to spend that time with my thoughts (and watching my safety on the road) I was better off mentally than when I was kidding myself that I was being productive.

I'm not saying you can't read or work on a commute, but it did not work for me in the slightest.