Complex sentence: EL petitioned for and was included in the formation of the federal government's Conrail, but the D&H was left out in order to maintain a semblance of competition in the northeast.
Split into simpler sentences: EL petitioned for and was included in the formation of the federal government's Conrail. The reason the D&H was left out of Conrail was to maintain a semblance of competition in the northeast.