Heading west in 1867, Palmer helped build the Kansas Pacific Railway. He befriended a young English doctor, Dr. William Abraham Bell, who became his partner in most of his business ventures. Generally Palmer took the role of president with Bell as vice president. The two men are best known as co-founders of the Denver and Rio Grande Railroad (Rio Grande). The Rio Grande and its successors eventually operated the largest network of narrow gauge railroad in the United States. They were ultimately absorbed by the 21st century Union Pacific Railroad.