The wife of a critically injured soldier in the Maine Army National Guard’s 133rd Engineer Battalion was en route Wednesday to Walter Reed Army Medical Center in Washington, where she was expected to see her husband.

Sgt. Harold Gray, 34, of Penobscot is one of three members of the unit who were injured when insurgents attacked their convoy in Mosul on Sunday.

Staff Sgt. Brian Wilson of Dixmont and Spc. James H. Kendall IV of Castine suffered minor injuries and were returned to duty after being treated by medical personnel.

Gray underwent six hours of neurosurgery in Iraq before being stabilized and flown to Landstuhl Regional Medical Center in Germany. After doctors concluded that he was stable enough to travel, the soldier was flown Wednesday to Walter Reed.

“He showed some good signs when they were preparing him to come here,” Gray’s mother-in-law, Gayle Hamm of Winterport, said Wednesday.

The soldier suffered injuries to both eyes and to his left arm and has shrapnel in his brain and chest, according to his father, George Gray.

The sergeant is in an induced coma to allow his brain to rest, but in preparing him for the flight, medical staff said that his legs twitched, according to Hamm.

“That’s a very good sign,” she said.

In addition to Gray’s wife, Laurie Gray, other family members are planning to visit the soldier in Washington.

No passengers on a Bangor flight were willing Thursday to give up their seats so that Gray’s wife, mother and father could travel together, family members said. The sergeant’s mother, Claudette Gray of Bangor, and brother, Dale Gray of Frankfort, are scheduled to fly out of Bangor International Airport early this morning. His father, George Gray of Penobscot, is waiting for the military to provide travel plans so he can visit his son. It is likely that he also will leave today.

Gray’s wife was scheduled to be met by a limousine driver at Reagan National Airport and taken to a hotel next door to the hospital.

Once on the ground, the soldier was to be taken by ambulance to the hospital, and the husband and wife were expected to arrive at about the same time.