Vintage duds for your little engineer!
Striped cotton denim hat with "Union Pacific" patch. Inside diameter is approximately 5 1/2".
Health Tex "Engineer" long sleeved shirt with 2 snap closure at the shoulder. Size 6 months. Fabric content is not on the label - I'm guessing it's a polyester knit. Nice and stretchy.
Both are in very good condition overall. The hat is a bit soiled on the inside band.

Thank you for looking!