ABC News has obtained the 911 call the unidentified father reportedly made around 8:20 a.m. while on a Massachusetts Bay Transportation Authority (MBTA) train.
"I left my 1-year-old baby in my SUV by accident this morning," the father said to a 911 dispatcher. "I am on my way back to the station now."
Quincy police, MTBA police and EMTs responded to the scene and found the baby safe in the car, ABC News affiliate WCVB reported, adding that the 1-year-old girl had been inside for about 35 minutes.
The MTBA police did not immediately respond to ABC News' requests for additional information, including whether the father would be charged with any wrongdoing. The Quincy Police Department told ABC News all media requests regarding the incident should be directed to the MTBA police.
The father, who wished to remain anonymous, said in a statement forwarded to ABC News by its affiliate, WCVB, that today was one of the worst days of his life and that he felt fortunate it was a "mild temperature" day.
"The baby had fallen asleep in the child seat and I went into auto pilot," he wrote. "I had what I thought was a safe-guard procedure against this in place that I neglected to use today. Obviously, we will be doing more to prevent this going forward."
He added that knowing too much time had already elapsed, he called police to ensure his daughter's safety.
"I'd like to thank the Quincy and transit police departments as well as the responding EMTs for taking good care of my little one while I rushed back," he wrote. "She is safe and happy today."