switcher locomotive
A switcher locomotive (American English), shunter locomotive (British English), or shifter locomotive (Pennsylvania Railroad terminology) is a locomotive used for maneuvering railway vehicles over short distances. Switchers do not usually move ...
, or as the PRR termed them "shifter". The PRR preferred the 0-6-0
wheel arrangement
In rail transport, a wheel arrangement or wheel configuration is a system of classifying the way in which wheels are distributed under a locomotive. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and c ...
for larger switchers, whereas on other railroads the 0-8-0 gained preference. The PRR generally used 2-8-0s when larger power was required.
History
Altoona Works constructed the prototype B6 in 1902. The B6 had the Pennsylvania's trademark square-shouldered
Belpaire firebox
The Belpaire firebox is a type of firebox used on steam locomotives. It was invented by Alfred Belpaire of Belgium in 1864. Today it generally refers to the shape of the outer shell of the firebox which is approximately flat at the top and sq ...
and drivers. They were constructed as
saturated steam
Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization ...
engines, rebuilt with superheaters later as class B6s, and had
Piston valves
Piston valves are one form of valve used to control the flow of steam within a steam engine or locomotive. They control the admission of steam into the cylinders and its subsequent exhausting, enabling a locomotive to move under its own power ...
and
Stephenson valve gear
The Stephenson valve gear or Stephenson link or shifting link is a simple design of valve gear that was widely used throughout the world for various kinds of steam engines. It is named after Robert Stephenson but was invented by his employees.
...
Lima
Lima ( ; ), originally founded as Ciudad de Los Reyes (City of The Kings) is the capital and the largest city of Peru. It is located in the valleys of the Chillón, Rímac and Lurín Rivers, in the desert zone of the central coastal part of ...
, in addition to Altoona, between 1902 and 1913.
The next version built was the B6sa, 55 of which were built at Altoona during 1913–1914. These had radial-stay fireboxes, common elsewhere but rare on the Pennsylvania, and they replaced the Stephenson gear with the more modern
Walschaerts valve gear
The Walschaerts valve gear is a type of valve gear used to regulate the flow of steam to the pistons in steam locomotives, invented by Belgian railway engineer Egide Walschaerts in 1844.
The gear is sometimes named without the final "s", since it ...
. Steam delivery pipes were outside, like all other PRR modern power. All were built superheated.
Finally, during 1916–1920, 238 of class B6sb were built. These were the final, definitive type, and had a Belpaire firebox, but were otherwise little changed from the B6sa. The final 97 locomotives had piston valves mounted outboard of the cylinders, instead of inbound as previously built, giving the cylinder assemblies an outward cant at the top, rather than inward.
All B6sa and B6sb locomotives were retrofitted with
power reverse On a steam locomotive, the reversing gear is used to control the direction of travel of the locomotive. It also adjusts the cutoff of the steam locomotive.
Reversing lever
This is the most common form of reverser. It consists of a long lever moun ...
to make the frequent back-and-forth of switching quicker and easier.
The last PRR locomotive in active service was #5244, leased to Union Transportation of
New Egypt, New Jersey
New Egypt is an unincorporated community and census-designated place (CDP) located within Plumsted Township, in Ocean County, New Jersey, United States.
Two B6s survive:
- B6sb #1670 was saved in the PRR's historic collection at
Northumberland, Pennsylvania
Northumberland is a borough in Northumberland County, Pennsylvania, United States. The population was 3,804 at the 2010 census.
History
A brewer named Reuben Haines, a native of Philadelphia, Pennsylvania, founded the town of Northumberland in ...
and was donated to the
Railroad Museum of Pennsylvania
The Railroad Museum of Pennsylvania is a railroad museum in Strasburg, Lancaster County, Pennsylvania.
The museum is located on the east side of Strasburg along Pennsylvania Route 741. It is administered by the Pennsylvania Historical and Mus ...
along with the majority of that collection.
- B6sa #60 is on a siding in Hockessin, Delaware, along the
Wilmington and Western Railroad
The Wilmington and Western Railroad is a freight and heritage railroad in northern Delaware, operating over a former Baltimore and Ohio Railroad (B&O) branch line between Wilmington and Hockessin. The railroad operates both steam and diesel lo ...
. It has a larger tender, from a 2-8-0 Consolidation, but it is intact, albeit in poor condition. In 2019–2020, it was donated to the Historic Red Clay Valley Inc., and the locomotive remains on a siding near Mt. Cuba.