A group of Roman Catholic nuns started the New York Foundling Hospital, a medical and care center for abandoned infants. The sisters chose to follow the Children's Aid Society in seeking new homes for the babies.

Wendinger: “What the Sisters of Charity did in 1869, many years later then the orphan trains beginning with the Children's Aid Society, was they set a basket out, a cradle, if you will, and any mother could leave a child she could no longer care for with no questions asked.”

Wahlmeier: “They started sending children out on their own version of the orphan trains. Those were called the mercy trains, or baby trains, because they focused on younger children. And you essentially ordered a child from the New York Foundling Hospital.”

Wahlmeier: “The New York Foundling Hospital had a little bit more of a family oriented selection process where they would write in, the families would write into the orphanage and say, I want a blue-eyed, blonde-haired boy and they would get a blue-eyed, blonde-haired boy. It was like ordering a child out of a catalog.”

Wendinger: “In my mother's case, what they did is they applied for a girl around the age of two with brown hair and brown eyes. And that is the way the Foundling's children were handled.”
 
Identification tags were sewn into the Foundling children's clothing to ensure they reached the proper family when arriving at a busy train station. They later shifted to placing numbers on the children. The Children's Aid Society typically tried to name a local committee to screen applicants for suitability prior to a train's arrival in their town. The Foundling Home instead asked a local priest to help find ideal parents for a child.