sentences:  The "front-engine, rear-wheel drive" layout (abbreviated as FR layout) is one where the engine is located at the front of the vehicle and driven wheels are located at the rear.This was the traditional automobile layout for most of the 20th century, and remains the most common layout for rear-wheel drive vehicles.The "mid-engine, rear-wheel drive" layout (abbreviated as MR layout) is one where the rear wheels are driven by an engine placed just in front of them, behind the passenger compartment.