CINCU, Romania — Deep in the hills of central Romania, a large portion of the U.S. Army's first rotational heavy brigade has converged for a large-scale, combined arms live-fire exercise to take place July 15.

Getting to the Center for Joint National Training in Cincu isn't easy by car. All of the arteries in and out of Cincu are narrow, winding roads occasionally blocked by herds of sheep.

But four of seven battalions from the 3rd Armored Brigade Combat Team, 4th Infantry Division out of Fort Carson, Colo. — with their M1 Abrams tanks, Bradley Fighting Vehicles and Paladin Howitzers, among many other vehicles and support equipment — all made it rapidly to positions on the surrounding hillsides to coordinate and execute a large-scale exercise with other Army units and multinational partners.

"It was a pretty massive endeavor moving the majority of the brigade here, and that is just here in Romania," Capt. Scott Walters, the brigade's spokesman, told Defense News just days prior to the big exercise.

The U.S. Army decided to begin implementing a new heel-to-toe, nine-month rotation of a heavy brigade into the European theater over a year ago, as the service is now geared toward providing a strong deterrence against Russian aggression in Ukraine and elsewhere in Eastern Europe.

The ABCT is the first of these rotational brigades, serving as the pioneer in Europe for ABCTs still to come.

With a large portion of the first ABCT positioned in the middle of Romania, the U.S. Army has been able to show "that we can have a heavy brigade presence here," Walters said. "This is the first time heavy brigades have been operating in Eastern Europe … on a continuous basis."

And while amassing a large amount of firepower in a complex scenario will be the Super Bowl for the brigade, just getting to Romania and around Eastern Europe and Germany has been an invaluable experience for units within the brigade, soldiers in the field told Defense News on Thursday.

The U.S. Army faced one of its biggest challenges in January as it relearned to rapidly deploy large units and all of its resident equipment back to Europe through seaports and by road and rail. Within 14 days after arriving at the seaport of Bremerhaven, Germany, the ABCT was in place in Poland and ready to fight, Maj. Gen. Duane Gamble, commander of the 21st Theater Sustainment Command at the time, said earlier this year.

But the brigade didn’t settle into one spot in Poland and instead spread out.

At the start of the deployment, one battalion headed to the Baltic region — Atlantic Resolve North — and another battalion deployed to Romania and Bulgaria — Atlantic Resolve South — while the bulk of the team stayed in Poland.

And how the ABCT dispersed became more complex as the deployment went on.

For Capt. Ryan Van Wie, the headquarters commander of the 1st Battalion, 66th Armor Regiment, his unit started in Karliki, Poland.

The unit then moved to Grafenwoehr, Germany, where it spent five months and completed large portions of training requirements from individual weapons qualification all the way to a culminating live-fire training exercise. Then it moved to Hohenfels, Germany, for the Combined Resolve 8 force-on-force exercise.

Picking up once more, Van Wie’s unit moved to Romania for CALFEX, part of Saber Guardian, the largest military exercise in Europe this year.

And after the exercise it will move back to Karliki.

Traveling heavy

Moving all of the heavy equipment by rail has quickly become second nature to the team, Van Wie described, despite having to move across borders and convoy equipment through regions where roads are more accustomed to a horse and buggy than an Abrams tank.

Several soldiers in the brigade said they’ve trimmed down the process of getting equipment locked down and ready to move by rail from a few days to just a few hours. Once off the rails in Romania, the battalion had to route the equipment around several bridges that couldn't bear the weight of 70-ton tanks and roughly 25 kilometers of road to get to the training center.

Mastering such a skill is vital, according to Lt. Gen. Ben Hodges, U.S. Army Europe commander, with units spread over huge swaths of territory. He recently asked for more allies to contribute in ways that enhance freedom of movement across borders and large territories by providing heavy equipment transport and other transportation, guaranteeing rail access and improving rail heads in order to be able to move a brigade by rail in 48 hours.

Always on the move

The brigade is also exercising what will likely be future operational scenarios, as well. Army leaders have stressed the need for troops to learn how to stay mobile to avert a near-peer adversary, to operate in dispersed and independent formations and be more self-sustaining.

Van Wie recalled rotations at the Joint Readiness Training Center during prior deployments where units lived at a Forward Operating Base and would return there every night after patrols. "Here in a decisive action environment, we are constantly on the move and so rarely do you stay in one location more than a day."

Over the course of two days at the CJNTC, the tactical operations command post for the exercise moved overnight to a different location and other units have been sleeping directly near their equipment. Paladin howitzer operators told Defense News they have spent some nights at the training center sleeping on top of the weapon system itself.

Another issue the ABCT has been working out is how to provide resupply for highly mobile and dispersed units who may be under indirect fire or whose resupply lines itself could be under attack.

"That was a big challenge that we had to learn to cope with," Van Wie said, "and I think by the end of the rotation we have definitely implemented several lessons in how we conduct resupply in a contested environment like that."

One of those is making sure resupply assets move just as much as the units do and another is simply making sure projections for supplies needed are accurate, he added.

International interoperability

Van Wie said his battalion has also learned a great deal in terms of how to work with multinational partners, whether it’s making different equipment work side-by-side on the battlefield, having communications set up so everyone can talk or what allied nations can bring to the table to enhance the force.

For example, the force-on-force training at Hohenfels was the first opportunity for the brigade to become multinational, incorporating a Ukrainian company, a Romanian company, a Hungarian battalion and an Albanian light infantry company.

The brigade refined and validated an effective, interoperable communications package with the allied nations there and got a sense of what each country could bring to the table or where the U.S. Army could enhance allies’ capabilities, Van Wie said.

Romanians and Ukrainians were effective in bolstering dismounted capabilities, including clearance operations in thick vegetation where tanks can’t go or conducting reconnaissance and clearance through urban centers within the training course in advance of a tank company.