Complex sentence: He worked as a research consultant and assistant to the President of the Chicago, Burlington and Quincy Railroad, and was also a research consultant for the Association of American Railroads as well as several regional railroad companies.
Split into simpler sentences: He worked as a research consultant and assistant to the President of the Chicago, Burlington and Quincy Railroad. He was also a research consultant for the Association of American Railroads, as well as, several regional railroad companies.