Given the question: Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. ALCO DL-109 - The ALCO DL-109 is one of six models of A1A-A1A diesel locomotives built to haul passenger trains by the American Locomotive Company (ALCO) between December 1939 and April 1945 (DL stands for Diesel Locomotive). They were of a cab unit design and both cab-equipped lead A units DL-103b DL-105 DL-107 DL-109 and cabless booster B units DL-108 DL-110 models were built.
The answer is:
Mean Of Transportation