[Hanover (Germany) = E-Daily Reporter LEE BAE-WOON ] A massive steel frame slowly rises above the truck production line. The chassis—the skeleton of a large truck designed to carry loads weighing tens of metric tons—looks less like an automotive part and more like a steel framework snatched from a construction site. Its appearance is completely different from that of a passenger car’s chassis.

At first glance, the chassis lined up in a row all look identical. But upon closer inspection, they differ slightly—from the large and small holes drilled throughout the steel frame to the number of tightly fastened bolts. This is because, unlike passenger cars that are mass-produced according to a standardized template, the body configuration of heavy-duty trucks varies significantly depending on customer requirements.

The deafening roar of metal striking metal, the shouts of workers urging each other on, and the incessant safety alarms all blend together. Amid the sweet, metallic scent lingering in the air, diesel engines on the right side of the line and drivetrains for electric trucks on the left wait quietly for their turn. How did these two components—which would rarely be found together under normal circumstances—come to stand side by side in the same place?

During a visit on the 18th to the MAN Truck & Bus plant in Munich, Germany, diesel trucks and electric trucks were being manufactured together on a single production line. Rather than building a separate line dedicated to electric trucks, this mixed-production approach integrates the electric truck manufacturing process into the existing line that has been producing diesel trucks for 70 years.

The MAN Munich plant has been producing countless trucks since 1955. On a site spanning over 100 hectares—equivalent to approximately 140 soccer fields—it manufactures the TGS and TGX series of heavy-duty trucks, as well as key components such as cabs and drive axles. This historic plant, which has shaped the history of diesel trucks, is now leading the era of commercial vehicle electrification by rolling out electric trucks on the same production line.

Monitors in front of the workers display the unique identification number of the vehicle being assembled, the parts to be installed, and the work sequence in real time. On one side of the screen, yellow numbers counting down the time remaining for the current process urge the workers to keep pace.

Although diesel and electric trucks are produced on the same line, the process proceeds calmly and without confusion. The secret lies in the “truck reference number” assigned to each vehicle. This number serves as a customized production sheet for each vehicle, containing everything from the drivetrain to the specific specifications ordered by the customer. Forklifts and automated guided vehicles also transport the parts required for each process precisely according to the truck reference number.

The massive robotic arms commonly seen in passenger car factories are nowhere to be found here. This is because, to flexibly accommodate the vast array of optional features, the skilled hands of workers are more efficient than automated equipment. A factory official explained, “Depending on the workload, anywhere from two to as many as ten people work together on a single process,” adding, “We also deploy support staff, whom we call ‘Jokers,’ wherever help is needed.”

The highlight of the assembly process is the so-called “marriage” process, in which the chassis and cab are joined together. The completed cab, suspended from a crane, is slowly lowered onto its matching chassis. One worker operates the crane while two others meticulously align the positions. As the cab is attached to the bare steel frame, the familiar silhouette of a large truck finally takes shape.

Just because the exterior is complete doesn’t mean the truck heads straight to the shipping yard. The truck undergoes visual and manual inspections at various stages of the process, and even after the cab is attached, it is thoroughly checked to ensure that all electronic devices and pneumatic systems are functioning properly. Only after a “YES” is recorded for every inspection item can the engine be started for the first time. If even a single problem is found, the truck is moved to a separate workshop for further inspection.

A factory official emphasized, “Not only does every vehicle undergo quality inspections at each stage of the production process, but we also randomly select finished vehicles every day to re-inspect them, including the undercarriage and the interior of the cab,” adding, “The precision inspection takes about half a day to ensure that even the smallest errors are caught without exception.”

Adding electric truck production to the existing production line was by no means a simple task. In 2021, MAN opened an “e-Mobility Center” spanning approximately 4,000 square meters at its Munich plant, replicating a real production environment to validate the battery and electric truck assembly processes in advance. In recent years, the company has also provided high-voltage technical training to more than 5,000 employees, transforming its existing workforce into production personnel equipped for the era of electrification.

An MAN official emphasized, “The key to mixed-model production is the ability to flexibly adjust the production ratio of diesel and electric trucks to meet market demand,” adding, “By utilizing existing equipment and skilled personnel, we can reduce the investment burden associated with the transition to electrification and minimize the risk of fluctuating plant utilization rates due to changes in demand.”