PRR Q2
Encyclopedia
The Pennsylvania Railroad
's class Q2 comprised one prototype and twenty-five production duplex
steam locomotive
s of 4-4-6-4
wheel arrangement
.
They were the largest non-articulated locomotive
s ever built and the most powerful locomotives ever static tested, producing 7,987 cylinder horsepower
(5,956 kW
) on the PRR's static test plant. They were by far the most successful duplex type. The duplex propensity to slip was combated by an automatic slip control mechanism that reduced power to the slipping unit.
Despite overall success, the Q2s were all out of service by 1951. With dieselization, they were the obvious first targets to be withdrawn since they were only a little more capable than the conventional J1
class 2-10-4
s but with far higher operating and maintenance costs.
Pennsylvania Railroad
The Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....
's class Q2 comprised one prototype and twenty-five production duplex
Duplex locomotive
A duplex locomotive is a steam locomotive that divides the driving force on its wheels by using two pairs of cylinders rigidly mounted to a single locomotive frame; it is not an articulated locomotive...
steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
s of 4-4-6-4
4-4-6-4
A 4-4-6-4, in the Whyte notation for the classification of steam locomotives by wheel arrangement, is one that has four leading wheels followed by four coupled driving wheels, a second set of six coupled driving wheels and four trailing wheels....
wheel arrangement
Wheel arrangement
In rail transport, a wheel arrangement is a system of classifying the way in which wheels are distributed beneath a locomotive.. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and connections, with the adopted notations varying by country...
.
They were the largest non-articulated locomotive
Articulated locomotive
Articulated locomotive usually means a steam locomotive with one or more engine units which can move independent of the main frame. This is done to allow a longer locomotive to negotiate tighter curves...
s ever built and the most powerful locomotives ever static tested, producing 7,987 cylinder horsepower
Horsepower
Horsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...
(5,956 kW
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
) on the PRR's static test plant. They were by far the most successful duplex type. The duplex propensity to slip was combated by an automatic slip control mechanism that reduced power to the slipping unit.
Despite overall success, the Q2s were all out of service by 1951. With dieselization, they were the obvious first targets to be withdrawn since they were only a little more capable than the conventional J1
PRR J1
The PRR J1 was a class of 2-10-4 or "Texas" type steam locomotives with driving wheels built between 1943 and 1944. The J1 had over of tractive effort, plus an additional if the booster engine was used.- Features :...
class 2-10-4
2-10-4
Under the Whyte notation for the classification of steam locomotives, a 2-10-4 locomotive has two leading wheels, ten driving wheels , and four trailing wheels...
s but with far higher operating and maintenance costs.