(The Washington Post)

On the front lines, the jagged teeth of a young soldier’s bulldozer mark the beginning of Iraq’s territory and the end of the Islamic State’s.

Pvt. Mohammed Ali al-Shwele is 19, weathered and lean. He has been shot at, rocketed and mortared while trying to protect the troops behind him. Using his cellphone, he captured one particularly harrowing moment, when a car bomb engulfed his armored behemoth in flames and shrapnel. The video went viral.

His minor celebrity status aside, Shwele and the cadre of bulldozer drivers like him are responsible for moving the war forward one block at a time. Iraqi officers won’t start an offensive without them, and if a bulldozer is knocked out with no replacement, the day’s operation is over.

“There can be no liberation without the bulldozer,” Shwele said.

Bulldozers were essential to Iraqi forces as they pushed through Ramadi, Fallujah and eastern Mosul. Unlike other breaching equipment, such as specialized explosives or specifically outfitted tanks, the bulldozers can clear obstacles while creating ad hoc defenses.

In western Mosul, with its crowded neighborhoods and increasingly complex ring of Islamic State defensive positions, the machines have become more crucial — and more of a target — than ever.

Soldiers such as Shwele, and the construction equipment they pilot, provide insight into what the fighting in the city has turned into after eight months of near-continuous combat. The battle is a daily grind, and despite the presence of drones, GPS-guided artillery and U.S. jets, the best way forward is still behind a mobile wall of steel.

Only a handful of neighborhoods in Mosul remain in the militant group’s hands — including the Old City, where tens of thousands of people live. The Islamic State has fortified these areas, digging trenches and clogging streets with earthen berms in an attempt to delay Iraq’s final push.

Once the main logistics hub for the Islamic State’s operations in Iraq and the birthplace of its self-declared caliphate, Mosul is critical for both sides. While Iraqi and U.S. officers have suggested that the fighting will end soon, some also have cautioned that the last stages of the battle will likely be the bloodiest.

As the final offensive begins, Shwele will be alone in the cab of his bulldozer, elevated 10 feet off the ground.

His job will be twofold: to break through the Islamic State’s defenses and to provide a barrier for whatever comes at the advancing troops behind him. Aside from screening for car bombs and acting as a mobile barricade with a top speed of just over 6 mph, his machine’s 12-foot-wide blade will also act as a de facto minesweeper.

Schwele’s dozer is a Caterpillar D7R, built in the United States. It is one of 132 sent to Iraq by the Pentagon since March 2015, according to data provided by the Defense Logistics Agency. It has additional armor but carries no weapons and weighs more than 32 tons. Websites price the civilian variant of the bulldozer at upwards of $200,000.

Around the time the United States was sending the first bulldozers to Iraq, Schwele joined the Iraqi Counter Terrorism Service, the U.S.-trained contingent of soldiers that has led nearly every offensive since the Islamic State swept across parts of Iraq three years ago. He wanted to see combat and instead was placed in a logistics battalion.

“I joined to fight, but then I realized that my job is more important than the job of the fighter on the ground,” he said.

Shwele fought in Anbar province as a bulldozer driver before being sent to Mosul. He described breaking through a berm in Fallujah under so much fire that the noise in his cab was deafening. Sometimes, Schwele said, he can still hear those bullets ricocheting off his machine even when he is far from the front.

Shwele’s two best friends — both bulldozer drivers — were killed in Mosul. One died in the eastern part of the city when a car bomb hit him, and the other a few months later after a recoilless rifle round tore through his cab.

Massive and slow, the vehicles are a favorite target of the Islamic State. When they appear at the end of a street, the militants target their engine with rockets and car bombs.

The car bomb that knocked out Shwele’s bulldozer earlier this month in the Ar Rafa’l neighborhood of Mosul sent steel into his left arm. He walked away but found his way back to the front 24 hours later.

As the counterterrorism forces moved to encircle some of the final neighborhoods of the city in May, three drivers were wounded in one day of fighting. With only one driver left, Maj. Ehab Jalil, a battalion commander for the unit, stopped the offensive.

The counterterrorism troops have lost eight bulldozers in eastern and western Mosul, according to their head logistics officer, Brig. Gen. Ali Jamal. Their burned-out hulks are scattered among the ruins of the city.

Last month, the Iraqi Federal Police put out a call for volunteers following the deaths of dozens of their bulldozer drivers in a battle. Mohammed Kareem Ahmed, 27, and Muhsin Harir, 40, both infantrymen, raised their hands

The men were given a 10-day training course on the tarmac of the Mosul airport before being sent to the front. They share a wheeled loader, nicknamed The Cutter, that does the same work as its tracked counterparts.

There are roughly 10 bulldozer drivers for Harir and Ahmed’s Federal Police division, and both say they need more people and at least three more bulldozers before they have what they need to go into the Old City.

Among one another, the bulldozer drivers within the Federal Police call themselves “The Suiciders,” a name bandied about with a grinning pride.

“The infantry, they can hide behind a Humvee or a berm,” Ahmed said. “I hide behind nothing.”