I commute to work every day and there is a woman I talk to every day because we take the same train. I've been talking to this woman for a few months (4+). We chat for a few minutes before the train comes every day. We are both married (and I'm a woman, too), but she is a lot older than me.
I'll be going on maternity leave soon and I might change my work schedule but I'd like to keep in touch with this person.
What's a non-awkward way to exchange contact information?