Simplify the following text for a Grade 4 native English-speaking person.
Original: Santa Fe was originally envisioned as an important stop on the Atchison , Topeka and Santa Fe Railway . But as the tracks progressed into New Mexico , the civil engineers decided that it was more practical to go through Lamy , a town in Santa Fe County to the south of Santa Fe .
Simplified: Santa Fe is the capital city of the U.S. state of New Mexico .