Meanings of motor rifle troops in English

Hals detested the squalid cellar where we were established, and following his lead, I volunteered for service in the motorized infantry.

Adolf Hitler, meanwhile, was in the process of rearming the country when he attended a war-gaming exercise that combined tanks and motorized infantry.

What about the Second Motorized Infantry Brigade?

General Kodorovich's command car rattled and bounced along the rough shoulder of the highway past his stalled 71st Motorized Infantry Division.