A Lisbon man died trying to save his two dogs from a train. Now, family and friends are fighting to rehab the one that survived.

Mark Sullivan dedicated his life to his love, Denise Chapman, his Labrador retrievers and the land.

A surveyor and environmentalist, he knew the woods better than his own backyard. He walked daily, trekking to the nearby cornfield and crossing the same train tracks on his four-mile route with his Labradors, Piper and Emma Lea, and his partner of 28 years, Chapman.

He’d trained his dogs, each under 2 years old, to halt at the sound of a train whistle. Decades ago, he’d lost one of his first Labradors to a train on a walk near the shoreline, so he had tried to prepare them for the risk.

On Nov. 14, while out on a walk, the labs started to cross the tracks when a train whistle blew. They knew that sound meant to stop, so they did. Right on the tracks.

Sullivan, 61, died when a train struck him as he reached to pull his dogs to safety, not far from his home on the Quinebaug River in Lisbon.

His 18-month-old chocolate lab, Emma Lea, was also killed by the train.

Piper, a 16-month-old black lab, survived with severe injuries. She was rushed in an ambulance to the Pieper Memorial Veterinary Hospital in Middletown, where her medical bills have already surpassed $17,000. Chapman now faces a daunting financial burden in the midst of her grief.

For two weeks, Piper has been receiving round-the-clock medical care to treat her wounds and help her recover from deep lacerations to her rear, a severed tail and a severed paw. Her tail was fully amputated, leaving not even a nub to wag when she gets excited over visits from Chapman. Parts of her paw had to be removed, too.

Faced with the loss of her life partner and dog and forced to leave Piper at the hospital, Chapman has been slowly adjusting to her new reality.

“Her whole life has been altered,” said Shaina Bogue of Norwich, who for decades has called Sullivan and Chapman her “unofficial adopted parents.”

“The house is very quiet now,” said Bogue. And so are the trails that Chapman still walks.

“It’s those moments when she’s alone and she’s on those walks that it sets in. They’re not here,” said Bogue.

To keep her comforted on the quiet nights until Piper comes home, neighbors have lent Chapman their own Labrador, Emmett, for company. She’s tried to keep up the daily dog walks, setting up a memorial for Emma Lea in their backyard and another for Sullivan by the train tracks where he died.

At his funeral last Saturday, Bogue delivered a tearful eulogy for the man she called dad, who her young son affectionately called “Papa.”

Nine months pregnant and due to give birth to her first daughter any day, Bogue said that Sullivan was the first man to show her what fatherhood meant and to set an example of what a marriage could be.

“He showed me that a man can be active and present in a child’s life,” said Bogue. “And he showed me that a man can love a woman unconditionally.”

Above all else, Bogue said Sullivan was faithful. Faithful to her, to Chapman, to his career, his community, and, of course, to his dogs.

“He was faithful to his animals up until his very last breath,” said Bogue.

He was humble and kind and humorous, she said. And, in the end, he was heroic.

“His compassion and love for animals was clear all the way up to the moment of his death — he died trying to save an animal. For him to think that a dog’s life was just as valuable as his own says so much,” said Bogue.

It was Labradors who brought Bogue to Sullivan, when she was just 11 years old, wandering down a long dirt road in Lisbon. She happened upon two dogs and decided to follow them. They led her to a house on the water — once a one-bedroom shack that the couple had built upon for years — and to Sullivan and Chapman, who would become a pillar of stability in her life.

Soon, she joined the couple on daylong canoeing trips on the river, weekend getaways to New Hampshire and trips to the theater at Christmas. They welcomed her in as one of their own at a time when she needed family figures, she said.

‘Usually, it’s the kid who brings a stray dog home, but this time it was the dogs who brought home a stray kid,” she said.

The couple always had a pair of Labradors, said Bogue, and planned their days around their long walks to exercise the energetic dogs. Their relationship was centered around their pets, whom they treated like their children, and their love of the New England wilderness. They spent much of their time exploring the region, mapping out trails and spots to visit throughout the year.

Sullivan had dedicated his studies and his successful career to studying the land he lived on.

He earned a bachelor’s degree in forestry in 1984 and later a master’s degree in environmental science from the University of Connecticut. He started his own business, Mark H. Sullivan Land Surveying and Environmental Consulting, in the 1990s and worked for nearly a decade as a senior surveyor for the state, according to his obituary.

He loved surveying, his obituary said, because it gave him the chance to walk in the woods even more and to get to know his neighbors. He loved “to chat with land owners, farmers or the old timers at the local breakfast nook, listening to stories of their families and properties,” and unraveling the history of his home state.

Sullivan was also an active part of his community with a long list of hobbies. A longtime member of the First Congregational Church of Norwichtown, he sang in the choir and earned a spot in the church league’s Hall of Fame after joining their softball team. He served on the inlands and wetlands committee and closely followed his favorite teams, the Boston Red Sox and Boston Bruins. He hiked and hunted whenever he could, even through 10 years of battling cancer: first bladder cancer, then liver cancer and most recently, a new diagnosis of kidney cancer.

Through it all, he spent 28 years with his so-called “partner in boots,” Chapman, who is fighting her own battle with Lyme Disease. He was the sole provider for their family, leaving Chapman with the task of “relearning how to live her entire life,” said Bogue.

But, Bogue said, at least she has Piper.

“Piper’s life being spared in this time is the one thing Denise is putting all her hope in as her whole life has just been altered,” Bogue wrote on a fundraiser she started to help Chapman with Sullivan’s funeral expenses and Piper’s medical bills.

The GoFundMe, launched a few days after the accident, has raised over $10,000 of its $30,000 goal.

“The vet bill is already at a whopping $17,000 and growing daily with an outlook of at least another week or two in the hospital,” Bogue said.

Piper is expected to go home next week. As the dog faces a long road of recovery, Bogue said all donations, even of $2, will help the woman she calls “mom” face the challenges that lie ahead.

“Every dollar is a blessing, especially in this season,” she said.

To donate to the GoFundMe, visit https://www.gofundme.com/f/mark-sullivan.