Pennsylvania Railroad E7s
PRR 7002 on display at the Railroad Museum of Pennsylvania
Type and origin Power type Steam Builder Altoona Works, Alco Build date The rebuilding of these locomotives began in 1916 Total produced 90
Specifications Configuration: ​  • Whyte 4-4-2 Gauge 4 ft 8+1⁄2 in (1,435 mm) Leading dia. 36 in (910 mm) Driver dia. 80 in (2,000 mm) Trailing dia. 50 in (1,300 mm) Length 68 ft 6 in (20.88 m) (including 55P58 tender)[1] Adhesive weight 118,400 lb (53,705.3 kg)[1] Loco weight 171,100 lb (77,609.7 kg)[1] Tender weight 89,050 lb (40,392.4 kg) Fuel type Coal Fuel capacity 12 t (11.8 long tons; 13.2 short tons)[1] Water cap. 5,800 US gallons (22,000 L; 4,800 imp gal)[1] Firebox: ​  • Grate area 55.5 sq ft (5.2 m2) Boiler pressure 205 psi (1,410 kPa) Cylinders 2 Cylinder size 22.5 in × 26 in (572 mm × 660 mm)
Performance figures Tractive effort 27,409 lbf (121,920 N)
Career Preserved One (No. 7002) preserved, remainder scrapped Disposition No. 7002 on display

The Pennsylvania Railroad's class E2, E3, E7 steam locomotives were of the 4-4-2 "Atlantic" passenger type, frequently called light Atlantics after the introduction of the heavier E6 Atlantics. All were similar in size and boiler capacity but differed in firebox type, valves and valve gear and cylinder diameter. Classes E2 and E3 were built simultaneously.

Starting in 1916 a rebuilding program converted ninety class E2a, b, and c to class E7s by replacing slide valves with piston valves and increasing cylinder diameter from 20.5 to 22.5 inches (520 to 570 mm). Fourteen class E2 were similarly converted to class E7sa. Ninety class E2a,d, E3a,d were converted to class E3sd. These improvements allowed many of the engines to remain in active service into the 1930s.

The sub-classes differed as follows:^{[2][page needed]}

In the first decade of the twentieth century classes E2 and E3 handled all of the fast passenger trains of the Pennsylvania Railroad. As train weights increased due to the switch to steel passenger cars and more cars per train, the “light” Atlantics were usually doubleheaded. Eventually, as Pacific class K2 and K3 became available, they were relegated to secondary service

This engine was built for the Pennsylvania Railroad in 1902 as Class E2 No. 7002. On the first westward run of the Pennsylvania Special (renamed the Broadway Limited in 1912) in June 1905 the conductor clocked the train over three miles just west of Lima, Ohio in 85 seconds, at a record speed of 127.1 miles per hour (204.5 km/h) (the claim is dubious, as the train averaged about 68 mph (109 km/h) from Crestline to Fort Wayne). No. 7002 was rebuilt to class E7sa in August 1916 and scrapped in 1935.

When the PRR was looking for an E7 class locomotive for preservation, they refurbished No. 8063 (an E2a from the PRR) and substituted No. 7002’s engine number and builder’s plate. No. 8063 is a PRR E2a built in 1905. The engine was donated to Railroad Museum of Pennsylvania in 1979 and put into operating order by Strasburg Rail Road where it ran for until December 20, 1989, sometimes doubleheading with PRR D16 No. 1223.