FORT CHAFFEE, Arkansas -- As the sun rose over Fort Chaffee Ark., the morning of July 21, 2010, Army Reserve engineers from the 671st and 341st Engineer Companies began assembling an Improved Ribbon Bridge across the Arkansas River as part of Operation River Assault.

Boats dashed in all directions across the river to retrieve bridge sections that dropped from CH-47 Chinook helicopters above, and trucks positioned on the river banks.

"You have to control all the work boats and make sure they are all in the right order and make sure the safety boat does its drills as well," said Sgt. Pierre Dubois of the 671st Engineer Company.

The Soldiers assembled the 320 meter temporary bridge in approximately 90 minutes; 30 minutes ahead of schedule.

"The Arkansas River offers the bridging units a realistic training opportunity," said Sgt. 1st Class William Richards, the 412th Theater Engineer Command's training non-commissioned officer. "Not only do they have to deal with the distance of the crossing, but the river flow as well."

Once completed, the company commanders known as "Bridge Masters" inspected the structure for completeness and safety. The bridge was then cleared for traffic, and Brig. Gen. Jimmy Fowler, the 412th's deputy commander, led a convoy of 27 tactical vehicles across the span.

"My younger soldiers learned so much I have no doubt in my mind, after this exercise, that these guys can now operate any of this equipment perfectly," said Sgt. Jacob Hibbeln of the 671st Engineer Company.

"I was with the "build" crew and they showed me how the bridge works, which latches to throw, and how to put it together properly," said Pfc. Corey Williams, a 671st Engineer Company Soldier taking part in his first Extended Combat Training. "I'm enjoying it, except I don't really like the heat."

The Arkansas River tested the engineers, and earlier that week United States Army Reserve Command ran an informal test of its own. Lt. Gen. Jack C. Stultz, the USARC commander, visited River Assault and observed the 412th and the 416th TECs working together. Both two star commands changed from engineer commands to theater engineer commands when the Army Reserve transformed from the Regional Support Structure to the current Functional Command Structure in Oct. 2009.

"I said I want two engineer commands that are responsible for the engineer assets I got in the Army Reserve," Stultz said. "And I want them in various stages of readiness, year one, two, three, four and deployed."

The 412th inherited all the engineer units east of the Mississippi River, and the 416th got the ones to the west, according to Maj. Gen. Paul F. Hamm, the 412th commander.

"Amazingly it divided up evenly," Hamm said. "We each got approximately 12,000 Soldiers...we each have three brigades; two engineer brigades and one Maneuver Enhancement Brigade."

During River Assault, the 412th was the executive agent, and one its subsidiaries, the 926th Engineer Battalion, maintained command and control of the subordinate units, most of which came from the 416th.

"We've all gelled together and things have worked out," Hamm said. "As we know, units will go into theater and they'll work with other units they're not necessarily accustomed to."

"I'm impressed," Stultz said, after spending two days at River Assault. He witnessed, and in some cases participated in, training that ranged from a demolition range, to bridging operations.

Stultz said the different types of training he saw at River Assault are examples of what Soldiers want.

"Don't waste my time," Stultz said. "If you're gonna train me, train me. And make it realistic. Don't make it...sitting in the class room listening to somebody talk. Put me out here on the water, let me put a bridge together, let me get hot and sweaty and dehydrated."

The fact that the Soldiers built the bridge and were able to get the vehicles across represents the true test of the training, according to Hamm.

"We spanned the river," Hamm said, from his vantage point on a nearby barge. "It's not often they get the opportunity to bridge a river with the size and velocity of the Arkansas."