In 1900 and 1901, Baldwin built 28 similar four-cylinder Vauclain compound Ten-wheelers for the Union Pacific. The first ten were numbered 1820 to 1829 and had drivers of 69 inches, what led to the designation T-69. The other 18, numbered 1830 to 1847, had drivers of 73 inches and were designated T-73. The cylinders of all had diameters of 15.5 and 26 inches, while the stroke was 28 inches. They were simpled between 1909 and 1913 with two cylinders of 20 inches in diameter. Later, they also received a superheater. In 1915, all were renumbered in the range between 1320 and 1347. Their retirements were between 1921 and 1932.