Can I actually make progress with only 20 minutes a day? Trying to learn Swedish on a commute.

I'm a busy professional and my only free time is my train ride to work. I’m finding it hard to retain complex Swedish grammar rules in such short bursts. Should I focus purely on listening to Swedish podcasts to get used to the language, or is it better to do short, intense drills? I need a strategy that works when I’m exhausted after work.