Complex sentence: The SD24 was the first EMD production locomotive to be built with an EMD turbocharged diesel engine, sixteen months before the four-axle (B-B) model GP20.
Split into simpler sentences: The SD24 was the first EMD production locomotive to be built with an EMD turbocharged diesel engine. The first SD24 was built sixteen months before the four-axle (B-B) model GP20.