Union Pacific Corp. agreed to acquire Norfolk Southern Corp. in a cash-and-stock transaction valued at $85 billion, forming a transcontinental rail

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

The largest rail union in the United States said on Tuesday it intends to oppose Union Pacific's proposed $85 billion acquisition of smaller rival Norfolk Southern in regulatory proceedings, citing concerns about how the largest-ever buyout in the sector will affect U.