Pipeline buffer hydrocarbon from catalytic cracker effluent

In the fractionation of hydrocarbon vapors from a catalytic cracking of a hydrocarbon oil producing cracked vapors including gases, cracked gasoline fraction, a light cycle oil and heavier, a pump-around fraction intermediate the gasoline fraction and said light cycle oil is recovered, stripped of gasoline constituents and as necessary treated for removal of sulfur compounds and then used to separate in a pipeline simultaneously flowing therein a gasoline and a distillate having a flash point of at least about 125 DEG F. Use of the recovered fraction permits the separation during transportaton in the pipeline while avoiding significantly changing the octane of the gasoline or the flash point of the distillate whether there be blending within the pipeline of the buffered fraction with the gasoline and/or with the distillate or at the receiving terminal in making the cut between the gasoline and the distillate.