A number of stocks fell in the afternoon session after bellwether United Parcel Service (UPS) reported weak earnings and withheld its full-year guidance, citing “macro-economic uncertainty” and low consumer sentiment.

Union Pacific said on July 29 that it had agreed to buy smaller rival Norfolk Southern for $85 billion, including debt, in a deal that would create the first transcontinental U.S. railroad.

The merger would create the United States’ first coast-to-coast rail network, spanning 50,000 miles and 43 states.