updated 05/08/2012 AT 3:00 PM ET
•originally published 05/09/2012 AT 8:00 AM ET
Sandra Bullock, meet Thomas the Tank Engine.
The actress recently took her 2-year-old son Louis to a meet-and-greet with a full-size version of the famous train – one of many Mommy-and-me outings for the inseparable duo.
“Being a mom is her total focus now,” a Bullock source tells PEOPLE in this week’s cover story. Along with her work, “Louis has become her whole life.”