The locomotives later grouped together as class E-1 comprised ten Camelback Consolidations acquired by the Delaware & Hudson in 1898 and 1899 for burning culm anthracite. The first three were rebuilt from one existing 4-4-0 and two 2-6-0 locomotives. The remaining five were newly constructed by Dickson and were initially classified as U-II before being redesignated E-1a.

Their wide Wootten fireboxes provided a grate area of 80.3 square feet. In addition to 170 square feet of direct radiant heating surface, the firebox contained a further 104 square feet in the so-called water bars. One locomotive was built as a compound, using comparatively large cylinders measuring 23 and 34 inches in diameter. It was later converted to simple expansion. This locomotive and the remaining members of the E-1 and E-1a classes were scrapped between 1927 and 1928.