Car-free toddler development

Upon arrival home last night, Angela reported the following conversation with H earlier in the evening:

H: Where Mama?
A: Mama is taking the train home.
H: Mama on the train?
A: Yep.
H: Mama go to Alewife?
A: Yep.

It's not in any of the books, but I believe this is a major developmental milestone. Our two-year-old knows our subway stop. It warms a car-free mother's heart.