Pennsylvania Railroad T1 Steam Locomotive Trust

Pennsylvania Railroad 5550

Artist's rendition of PRR 5550 when finished.

Type and origin Power type Steam Builder Pennsylvania Railroad T1 Steam Locomotive Trust Build date 2014–Appx. 2030

Specifications Configuration: ​  • Whyte 4-4-4-4 Gauge 4 ft 8 1⁄2 in (1,435 mm) Driver dia. 80 in (203 cm) Wheelbase 107 ft (33 m)  • Engine 51.92 ft (16 m)  • Drivers 25.33 ft (8 m) Length 122 ft 9 3⁄4 in (37 m) Width 10 ft 0 in (3 m) Height 15 ft 10 in (5 m) Frame type Rigid Adhesive weight 279,910 lb (126,965 kg) Loco weight 502,200 lb (227,794 kg) Tender weight 443,500 lb (201,168 kg) Total weight 944,700 lb (428,509 kg) Tender type 180-P-84 Tender Water cap 19,200 US gal (72,680 L) Firebox:  • Firegrate area 92 sq ft (9 m2) Boiler: ​  • Diameter 91 1⁄2 in (2 m)  • Tube plates 214 13⁄16 in (5 m) Boiler pressure 300 psi (2,068 kPa) Heating surface 5,639 sq ft (523.9 m2)  • Firebox 490 sq ft (46 m2) Superheater: ​  • Heating area 1,430 sq ft (133 m2) Cylinders Four Cylinder size 19.75 in × 26 in (502 mm × 660 mm) Valve gear Franklin Type B2 rotary-cam Valve type Poppet

Performance figures Maximum speed Planned to be more than 126 mph (203 km/h)

Career Operators Pennsylvania Railroad T1 Steam Locomotive Trust Class Pennsylvania Railroad T1 Number in class 53 Numbers 5550 Disposition Currently under construction.

Pennsylvania Railroad 5550 is a mainline steam locomotive currently under construction in the United States of America. Upon completion, the locomotive will be the 53rd addition to the Pennsylvania Railroad's T1 steam locomotive class with an approximated year of completion date set for sometime around 2030. The total estimated cost of PRR 5550 is US $10,000,000. The project is following some of the same protocols and objectives faced during the prior construction of the LNER Peppercorn Class A1 steam locomotive Tornado in the United Kingdom to help ensure its success. The T1 Trust has also worked closely with many United Kingdom based steam locomotive foundations to aid in the construction of PRR 5550. Construction of the locomotive began in 2014 with the casting of the proposed locomotive's keystone shaped number plate with several other key pieces such as two of the large Boxpok driving wheels either complete or under construction as of April 2017.

The Pennsylvania Railroad's T1 class steam locomotive was one of the most unique and controversial class of locomotives ever constructed. This was due to its unusual Duplex drive 4-4-4-4 wheel arrangement, its use of the Franklin Type A oscillating-cam poppet valve and its characteristic streamlining conceived by famous industrial designer Raymond Loewy. The T1 was also the only class of Pennsylvania duplexii able to fit anywhere on the railroad's network. The T1 was also the first production series locomotive designed to use the poppet valve. The two prototype T1 locomotives were constructed in 1942 by the Baldwin Locomotive Works, numbered 6110 and 6111 respectively. Of the production series for the T1 class, with 25 locomotives Numbered 5500 to 5524 being constructed at the Pennsylvania Railroad's Altoona Works and the other 25 locomotives Numbered 5525 to 5549 being constructed at Baldwin. In total, 52 T1 class locomotives were constructed including the two prototypes. This made the T1 the most numerous engine produced of all the Pennsylvania Railroad's duplex drive locomotives.