Original: A total of 512 Class 47s were built at Crewe Works and Brush 's Falcon Works , Loughborough between 1962 and 1968 , which made them the most numerous class of British mainline diesel locomotive .
Simplified: The British Rail Class 47 ( Originally Brush Type 4 ) is a class of British railway diesel-electric locomotive that was developed in the 1960s by Brush Traction .