WASHINGTON — Louisiana Sen. Bill Cassidy and his wife, Dr. Laura Cassidy, were among a handful of physicians aboard a chartered train carrying dozens of GOP lawmakers to a Republican policy retreat when it struck a garbage truck in rural Virginia.

The Cassidys joined several other doctors pouring off the train to help the three-man crew aboard the truck, one of whom was killed in the collision. None of the lawmakers on the train, including Rep. Garret Graves of Baton Rouge, nor any of their aides traveling to the retreat, were seriously injured.

Sen. Cassidy said one of the survivors on the truck — treated in the immediate aftermath by the lawmaker physicians — was seriously injured in the collision. The third man, whom Cassidy believed to be the driver, walked away “with minor scrapes.”

Amtrak spokeswoman Beth Toll said two crew members and two train passengers were taken to a local hospital with minor injuries after the incident, which happened about 11:20 a.m. in Crozet, Virginia, about 15 miles west of Charlottesville and nearly two hours into the trip from Washington.

Alex Prevost, a University of Virginia health system spokesman, said it had received three patients and two more were on the way. He could not confirm a fatality.

Minnesota Rep. Jason Lewis' staff members tweeted that the first-term congressman was among those taken to the hospital. The tweet from Lewis' account said he was being checked for a concussion because of the impact.

Tennessee Rep. Chuck Fleischmann told The Indianapolis Star he was standing with a cup of coffee when the train hit the truck, throwing him. He suffered neck, back and foot injuries.

“I’m in a bit of shock right now,” Fleischmann told The Star. “I’m in a whole lot of pain and discomfort.”

Cassidy said he’d been napping at the time of the collision when he was jolted awake by “a sudden loud noise and a jolt.” People who’d been standing on the train were thrown to the ground while others suffered minor scrapes, bruises and bumps, he said.

Cassidy, a gastroenterologist, and Dr. Laura Cassidy, a retired trauma surgeon, both made their way off the train to help treat those in the truck. Cassidy said other medically trained members of Congress — including Rep. Brad Wenstrup of Ohio, a doctor and Iraq War veteran — were already tending to the injured when they arrived.

The physicians on board the train “literally pried open the doors and jumped off the train to assist those injured,” Rep. Barry Loudermilk, a Georgia Republican, told the Washington Post.

The senator said he held up the legs of the seriously injured man to try to keep blood flowing to his head while other members of Congress, Rep. Brad Wenstrup of Ohio and Rep. Larry Bucshon of Indiana, treated his injuries.

"He was breathing but he was full of blood," Wenstrup said of the man in an interview with the Cincinnati Enquirer. "I was able to check to see if he had blood in his mouth. A good sign was he tried to bite back."

Laura Cassidy joined another group — including Bucshon’s wife, Kathyrn, an anesthesiologist, and Rep. Phil Roe of Tennessee — in unsuccessfully attempting to save the man who died in the crash, attempting to open an airway and performing CPR but to no avail.

“It was pretty awful,” Bucshon told The Indianapolis Star. “We did what we could for the gentleman who was still living. Unfortunately, we couldn’t do anything for the other gentleman.” Other doctors on board included Reps. Michael Burgess, of Texas, and Roger Marshall of Kansas.

Wenstrup, a surgeon and Army Iraq War combat veteran, was also on the field for a congressional Republican baseball practice in June when a politically motivated gunman opened fire, critically wounding Louisiana Congressman Steve Scalise, R-Jefferson Parish, with a rifle round through the hip.

Scalise has credited Wenstrup, who applied a tourniquet to the Jefferson Parish lawmaker to staunch the bleeding, with saving his life.

Graves, the only other Louisiana congressman on the train, was fine after the crash, according to a spokesman for the congressman.

Rep. Clay Higgins was driving separately to the retreat with Rep. Randy Weber, R-Texas, who tweeted that they were both "safe."

Scalise tweeted that he was not on the train and that members of his staff who were on board were safe.

The policy retreat, an annual event, is scheduled to last three days at the Greenbrier resort in White Sulphur Springs, West Virginia. It’s scheduled to feature speeches from President Donald Trump and Vice President Mike Pence. By early afternoon, lawmakers were boarding buses to resume their trip and Pence was still planning to address them later Wednesday.

Rep. Kevin Cramer, R-N.D., was conducting a live interview with a local radio station when the accident occurred.

"Oh, Jesus, Sorry about that, we hit a bump here," he told AM 1100 The Flag, a station in Fargo, North Dakota. Later, he described the truck's wreckage and said, "Valuable lesson, people. Do not challenge a train at a crossing."

House Speaker Paul Ryan, R-Wis., was on the train and was unhurt, aides said.

Rep. James Comer, R-Ky., said about 100 Republican lawmakers were on the train when the crash occurred, which made him jump out of his seat.

"I looked out the side of the window and then I could see a truck, just in pieces out the side of the window," Comer said. "It was a garbage truck that was apparently, I would assume, trying to cross the tracks."

Comer said Capitol Police quickly jumped off the train, but came back and asked for any doctors to help. Comer said lawmakers performed CPR on one person.

Cassidy said the force of the collision mangled the garbage truck and derailed the lead engine of the Amtrak train. A second engine towed the train back to a station, where buses picked up the lawmakers.

Advocate staff reporter Bryn Stole and the Associated Press contributed to this report.