The D&H ordered nine C628 units built in the Spring of 1964, followed by nine more a year later. The D&H C628's, No. 601-618, were the Railroad's first big power and were used system-wide for about 15 years. In their later years on the D&H, they were commonly seen on the run-through trains established with the Lehigh Valley, NE-87 and NE-84, which provided expedited service between the South and New England. The C628's of both railroads put on impressive shows on the steep grades encountered on this route. By the mid-1970's, the D&H, which had been committed to six-axle power, underwent a change of policy in favor of four-axle power. This, and the Railroad's deteriorated financial condition, resulted in the acquisition of second-hand four-axle power and the disposition of virtually all of its six-axle locomotives. In 1978 the C628's were sold to Diesel Supply International, and they were leased to the National Railways of Mexico, operating there until the late-1990's. Arguably the Delaware & Hudson was historically Alco's most faithful customer, and the C628's marked the Railroad's last purchase of locomotives from Alco. However, in no sense did this fact end the D&H's acquisition of products of Alco. Among the D&H's second-hand acquisitions were the former Lehigh Valley C420's, obtained at the formation of Conrail, and later, Conrail C424's and a C420.