It’s a moment most subway riders barely notice: a conductor leans out of a train, ensuring everything is in order as the doors open. But for photographer Sirui Ma, that fleeting glimpse became the focus of her new book, “Subway Portraits.”

The book features candid images of conductors taken at stations tied to Ma’s own life, while also delving into the personal stories of these workers.

“I did set out to do it because I think the project was a way for me to explore my curiosities about subway conductors, what their days entail, and what their job looks like on a day-to-day basis,” Ma said during an appearance on “Mornings On 1” Wednesday.

Ma said she got consent from each conductor to take their portrait and the response from workers and their families has been overwhelmingly positive.

“Since the book came out, maybe some of their friends or relatives have seen the project online and tagged them into my Instagram or what have you,” she said. “And some of them were like, super surprised. They were like, ‘Oh, that's my dad.’ ‘That's my dad-in-law.’ And then one of them actually was super grateful that the project came to be a book, and she was like, ‘Thank you for seeing us. There's so much negativity around the job.’”