When the Moynihan Train Hall was unveiled to the public this month, it was hailed as one of New York’s most important public works projects in recent memory, a symbol of the city’s resilience through one of its darkest years. New Yorkers marveled at the acre of glass splashed across its 92-foot-tall atrium and the century-old steel trusses holding the large skylight in place.But looming over the opening was a story of private tragedy.For nearly a decade, one man, Michael Evans, had quietly shepherded the project to transform the historic Farley Post Office Building into a stately extension of the much-maligned Pennsylvania Station.Though out of public view, Mr. Evans’s work would come to define the new hall and help ensure its legacy as one of New York’s architectural jewels, his colleagues say.As project manager, he fought to preserve original steel trusses, brought in installations from world-renowned artists, traveled to a quarry in Tennessee to choose the best marble and paid his own way to Germany to personally inspect the glass that was manufactured for the large atrium.But Mr. Evans, 40, never saw the product of his painstaking work. Nearly 10 months before the Moynihan Train Hall officially opened, he took his own life.It is impossible to know what drives a person to suicide. But in his final months, his mental state took a turn for the worse as pressure grew to finish the project and stress mounted over costs, according to dozens of interviews with friends, family and colleagues.“Everyone who knew how much of his heart and soul he put into it, down to the tiniest details, will always go in there and feel Michael’s presence,” said Holly Leicht, an executive at Empire State Development, the state’s economic development agency, which oversaw the project.Like generations of wide-eyed transplants before him, he was hooked by the promise and possibility of New York from the moment he moved to the city.Born in Cali, Colombia, and raised in Dallas, he landed in New York after studying history at the University of Sydney and earning a master’s degree in international relations from Oxford University in England. A floppy-haired idealist with an athletic build and a natural charm, Mr. Evans met another American student at Oxford, Brian Lutz, and fell in love.Image“He had this quietly tortured look on his face,” Mr. Lutz, right, said of Mr. Evans as he raced to meet an accelerated deadline for finishing the project. Credit...Neal ThomasAfter Mr. Evans graduated in 2005, he and Mr. Lutz moved to New York. As Mr. Evans bounced between temporary jobs, he took daylong bike rides through the boroughs and ventured to far-flung neighborhoods.“There was never a neighborhood we went to where his curiosity didn’t come alive,” said Christopher Rizzo, a friend who accompanied him on these outings. “He was fascinated by urban design and thought it was a tragedy that so much of what we have built in New York has been so subpar.”Two years later, Mr. Evans landed a