Complex sentence: The three cylinders were provided with rotary cam poppet valves with the camshaft divided into two parts, independently driven from each side of the engine, which avoided complete immobilisation in case of a breakdown on a long stretch of single track.
Split into simpler sentences: The three cylinders were provided with rotary cam poppet valves, the camshaft being divided to two parts, independently driven from each side of the engine. This avoided complete immobilization in case of breakdown on a long stretch of single track.