I love the engine noise of the DD51. It's different from the sounds of North American train locomotive engines, which are larger.(Many of them use a single engine, ranging from 600HP in the early locomotives (1930's) to modern 4400HP engines. (there were a few 5000HP and 6000HP locomotive engines but I will exclude them because they were a failure) They can have a displacement of about 10 to 16 liters per cylinder!)