Pennsylvania Railroad E6 class

PRR E6s
E6s #1067 in its builders' photograph.
Type and origin Power type steam Designer Alfred W. Gibbs Builder PRR Juniata Shops Build date 1910–1914 Total produced 83
Specifications Configuration: ​  • Whyte 4-4-2  • UIC 2'B1' Gauge 4 ft 8+1⁄2 in (1,435 mm) Wheelbase 29 ft 7.5 in (9.030 m) Length 41 ft 3.5 in (12.586 m) (locomotive only) 72 ft 6 in (22.10 m) (including tender) Width 10 ft 0 in (3.05 m) Height 15 ft 0 in (4.57 m) Axle load 66,000 lb () Adhesive weight 136,000 lb (62,000 kg) Total weight 401,600 lb (182,200 kg) Fuel type Soft coal Fuel capacity 25,000 lb (11,000 kg) Water cap. 7,000 US gal (26,000 L) Firebox: ​  • Grate area 55.13 sq ft (5.122 m2) Boiler pressure 205 psi (14.1 bar) Heating surface: ​  • Firebox 218 sq ft (20.3 m2)  • Tubes 1,900.66 sq ft (176.577 m2)  • Flues 777.54 sq ft (72.236 m2)  • Total surface 2,896.20 sq ft (269.066 m2) Superheater: ​  • Heating area 980 sq ft (91 m2) Cylinders 2 Cylinder size 26×23½ in (660×600 mm) Valve gear Walschaert
Performance figures Tractive effort 31,275 lb () Factor of adh. 4.35

Class E6 on the Pennsylvania Railroad was the final type of 4-4-2 "Atlantic" locomotive built by the railroad, and second only to the Milwaukee Road's streamlined class A in size, speed and power. Although quickly ceding the crack trains to the larger K4s Pacifics, the E6 remained a popular locomotive on lesser services and some lasted to the end of steam on the PRR. One, #460, is preserved at the Railroad Museum of Pennsylvania.

Design

The E6 design was the responsibility of the Pennsy's General Superintendent of Motive Power, Lines East, Alfred W. Gibbs, and his team of designers. They produced an Atlantic of unusually modern design, featuring a very large and free-steaming boiler, outside Walschaert valve gear, piston valves on the cylinders, and a modern cast steel KW pattern trailing truck designed by the PRR's Chief Mechanical Engineer, William F. Kiesel, Jr. On the other hand, modern features never present on the E6 design, and never retrofitted, included the mechanical stoker, power reverse or a feedwater heater.

Prototypes and testing

Dimensioned drawing of an E6s.

A single prototype E6 locomotive, #5075, was turned out by the PRR's Juniata Shops in 1910; after the railroad's normal fashion, it would embark on a lengthy process of testing and experimentation before a production order was placed.

Given that by 1910 the larger 4-6-2 "Pacific" type was the accepted express passenger locomotive, it was somewhat contrarian for the PRR to be considering a new Atlantic class for that service. The E6, however, proved Gibbs et al. correct. The boiler proved free-steaming enough to enlarge the cylinders not once but twice; the stroke remained constant at 26 in (660 mm) stroke, but the bore began at 22 in (560 mm) and was enlarged to 23 in (580 mm) and finally to 23.5 in (600 mm).

Power output, when tested on rollers of the PRR's static test plant in Altoona, came out to 2,488 hp (1,855 kW) at the drawbar. Road testing on the flat Fort Wayne Division showed the locomotive achieving an average of 75.31 mph (121.20 km/h) from start to stop over the 105-mile route with a nine-car train, as well as 66.6 mph (107.2 km/h) with a thirteen-car train and 58.05 mph (93.42 km/h) with a fifteen-car train. At speeds over 40 mph (64 km/h), the E6 equaled or bettered a K2 Pacific. Furthermore, these results were achieved with the original cylinder bore.

Superheating was also applied after these tests, and proved itself so well that all other locomotives in the class were built superheated as class E6s, including two further prototypes.

Also tested, on prototype #1092 classified E6sa, were rotary valves designed by O. W. Young, actuated by regular Walschaerts gear. These proved successful but insufficiently so to be ordered on production locomotives over the reliable piston valve.

Production and service

Following the successful testing of the prototype locomotives, the PRR ordered a production run of a further eighty locomotives which were delived in 1914. All were fitted with superheaters. They were largely assigned to main line limiteds between Jersey City or Manhattan Transfer and either Washington, DC or Harrisburg, Pennsylvania, although they sometimes ran through to Altoona, Pennsylvania. Larger locomotives were generally used on the mountain grades past Altoona.

All locomotives were fitted with boxy oil-fired headlights from new, and the production locomotives had long tailrods projecting from the front of the cylinders. The tailrods were soon removed, as they were on other PRR classes that had them, and the oil headlights were replaced by electric units and turbogenerators, the latter sited between the headlamp and the stack.

As K4s Pacifics became available in greater numbers in the 1920s, the E6s locomotives were displaced from top-flight trains, but continued in service in lesser assignments, and particularly along the New Jersey seashore routes. Nine locomotives were transferred to the rosters of the Pennsylvania-Reading Seashore Lines, and including those, all 83 of class E6s were still in service in 1947. Some locomotives were leased by the PRR to subsidiary Long Island Rail Road.

Lindbergh run

Celebrated pioneer aviator Charles Lindbergh returned to the United States on June 11, 1927 after his successful solo transatlantic flight from New York City to Paris; he was greeted by President Calvin Coolidge at Washington, DC and awarded the Distinguished Flying Cross. There was intense competition between several newsreel companies to be the first to get footage of the ceremony back to New York to show in the Broadway theaters. Several companies chartered aircraft, but the International News Reel Corporation instead chartered a special train from the Pennsylvania Railroad, repeating what it had done for President Coolidge's inauguration.

While a plane could certainly get from Washington to New York faster than a train, the train could be equipped with a mobile darkroom to develop the film en route, thus making the rail alternative competitive. PRR management seized upon the opportunity to make headlines, and set everything up for a record run. All other trains would be moved out of the way to allow the Lindbergh newsreel special to pass.

E6s Atlantic #460 was selected as the locomotive, as one recently overhauled but having had time to "run in" following the work; B60B baggage car #7874 was equipped as a mobile darkroom, and P70 coach #3301 brought up the train to carry PRR and newsreel company officials. The crew were given permission to run as fast as they considered safe. The E6s tender was large enough to not need refueling for the run, and the water scoop would allow water to be picked up from track pans without stopping. Unfortunately, the scoop was damaged during the first pickup attempt and an unscheduled three-minute stop near Wilmington was needed to repair it and fill up from a standpipe.

The train made it to the electric changeover at Manhattan Transfer with an average speed of 74 mph (119 km/h), a record never beaten by steam on that journey, and with a reported maximum speed of 115 mph (185 km/h). The newsreels brought by train reached the cinema screens beat those flown to New York by over an hour, due to the delay the latter experienced to process the film. The Pennsylvania Railroad used this victory extensively in publicity in the following years.

It is no coincidence that of the 83 class E6s locomotives, it was the "Lindbergh Engine", #460, that was selected for historic preservation.