FORT LEONARD WOOD, Mo. -- Soldiers from the Fort Riley, Kansas-based 1st Infantry Division, conducted a combined arms gap crossing exercise with the 4th Maneuver Enhancement Brigade, here, Aug. 18-21.

The brigade's 5th Engineer Battalion spearheaded the operation, which involved several units across the "Big Red One" joining to build a bridge across a body of water.

"We came together this week as a unified maneuver enhancement team to support a 1st Infantry Division gap crossing exercise," said Col. Andy Munera, commander, 4th Maneuver Enhancement Brigade, or MEB.

Munera said each of the brigade's battalions played a significant role in the training. While the 5th Eng. Bn. took the lead in wet and dry gap crossings and provided logistical support, the 92nd Military Police Battalion provided security. The 94th Engineer Battalion's Soldiers portrayed hostile forces and the brigade's Headquarters and Headquarters Company served as mission command.

The 50th Multi-Role Bridge Company, 5th Eng. Bn., led the main effort of the operation by erecting three separate bridges -- two for water crossing and one for dry land. The first of the water bridges was a float raft emplaced as a temporary measure to establish security. In a real-world situation, the float raft could even facilitate humanitarian efforts. The second of the water bridges was a full-closure bridge to be used for continuous traffic conditions.

First Sgt. Benjamin Barrett, senior enlisted adviser for 50th Multi-Role Bridge Company, 5th Eng. Bn., said rafting was sometimes on the company's training calendar, but the unit rarely got to work on a full-closure bridge, and having air-lift support as part of the training was even rarer.

Barrett said about 90 percent of his junior Soldiers have never had the opportunity to build a full-closure bridge.

Aviation personnel with the 1st Inf. Div., who initiated the bridge construction by dropping equipment into the water, were impressed with the synchronization of all elements.

"It was great. The pieces that we moved were so out of the ordinary," said Capt. Rachael Tax, commander, Company B, 2nd General Support Aviation Battalion, 1st Combat Aviation Brigade, 1st Inf. Div., noting that her unit usually trains with concrete blocks at Fort Riley. "It added a whole new training element."

Tax said the scope of all the moving pieces made the gap crossing successful.

"It's humbling to see how small the role we had in the entire operation," Tax said.

While the bays used to erect the floating bridges were huge, Army tanks were even bigger and heavier.

"We provide freedom of movement for anybody, and this (line of communication) bridge is designed to hold the heaviest vehicles in the Army's fleet," said Sgt. Mitchell Kleve, a bridge crew chief with 50th Multi-Role Bridge Company.

The third type of bridging effort resulted in a dry-support bridge, which closed a gap caused by a natural depression.

Sgt. Cameron Riggs, a bridge crew member with 50th Multi-Role Bridge Company who assisted in the dry-support bridge build, said the most important aspect to these types of gap crossings was to determine the type of soil on the abutments, or edges. Riggs said if the soil was too loose or sandy to support the heavy military equipment crossing it, then horizontal engineers were called in to stabilize the area before the bays were emplaced.

The training scenario spanned over several miles, and included two fictional countries that were at war with each other.

"We developed a scenario in which the country of Danubia requested the assistance of the United States in repelling the invasion of Ariannan forces from their sovereign territory," said Lt. Col. Sebastien Joly, commander, 5th Eng. Bn., 4th MEB. "The 5th Eng. Bn., under the 4th MEB, served as the crossing force engineer for 1st Inf. Div. attack in pursuit of the retreating Ariannan forces."

To further support the realistic training as part of the initial security force, the 1st Inf. Div. sent in the cavalry.

"At first, I wasn't completely sure we wouldn't get onto the bridge and just roll off to one side," Staff Sgt. Jeffrey Mally, a cavalry scout with Headquarters and Headquarters Company, 1st Combined Arms Battalion, 63rd Armor Regiment, 2nd Armored Brigade Combat Team, 1st Inf. Div., said of his Bradley Fighting Vehicle. "I have never crossed the water like this before, but it is definitely good training for our Army's future operations."

The 4th MEB-led training operation concluded with 1st Combined Arms Battalion, 63rd Armor Regiment tanks, Humvees and armored personnel carriers maneuvering down a road that took them into "enemy territory," littered with simulated land mines.

"After completing the bridges, the (1st Inf. Div.) scouts and a sapper platoon from the 515th Sapper Company, conducted a movement to contact into an objective, using demolitions effect simulators to enhance their in-stride breach training," Joly said.

Once the combat engineers exited their vehicles and breached the obstacle with simulated explosives to detonate the mines, their mission was complete.

"I like this type of training," said Spc. Cody White, a combat engineer with 515th Sapper Co., 5th Eng. Bn., who rode in the convoy and participated in the breach operation. "This was fairly similar to my deployment minus the land mines -- there were IEDs instead."

A fully synchronized gap crossing exercise of this scale does not happen often, so sharing the knowledge gained was important for future training.

"I am very proud of the efforts of our leaders and Soldiers in the 'Dauntless' Brigade,'" Munera said. "Their efforts highlighted the unique technical expertise and extensive planning required to execute a large division-level combined arms gap crossing, and provided valuable lessons to the entire Army."