PRR Q2

Infobox Locomotive
name=Pennsylvania Railroad class Q2
powertype=Steam

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caption=PRR Q2 prototype #6131
designer=
builder=PRR Altoona shops
ordernumber=
serialnumber=
buildmodel=
builddate=1944–45
totalproduction=26
whytetype=4-4-6-4
uicclass=2'BC2'
gauge=RailGauge|ussg
leadingsize=convert|36|in|mm|abbr=on
driversize=convert|69|in|mm|abbr=on
wheelbase=convert|26|ft|4.5|in|m|abbr=on (driving)
convert|20|ft|4|in|m|abbr=on (rigid)
convert|53|ft|5.5|in|m|abbr=on (locomotive)
convert|107|ft|7.5|in|m|abbr=on (locomotive and tender)
length=convert|124|ft|7.125|in|m|abbr=on (locomotive and tender)
width=convert|11|ft|4|in|m|abbr=on (storm windows open)
height=convert|16|ft|5.5|in|m|abbr=on
weightondrivers=convert|393000|lb|kg|abbr=on
weight=convert|619100|lb|abbr=on
tenderweight=convert|430000|lb|abbr=on
locotenderweight=convert|1049100|lb|abbr=on
tendertype=PRR class 180F84, 8 axles, with conductor "doghouse"
fueltype=Soft coal
fuelc
convert|39.86|long ton|abbr=on
waterc
convert|19020|usgal|abbr=on
poweroutput=convert|7987|hp|kW|abbr=on
railroad=Pennsylvania Railroad
roadnumber=6131, 6175–6199
lastrundate=1951
frontcylindersize=19¾ in × 28 in
rearcylindersize=23¾ in × 29 in
boilerpressure=300 lbf/in²The Pennsylvania Railroad's class Q2 comprised one prototype and twenty-five production duplex steam locomotives of 4-4-6-4 wheel arrangement.cite book
title = Pennsy Power
author = Staufer, Alvin
year = 1962
publisher = Staufer
id = LOC 62-20872
pages = 216–225] cite book
title = Loco Profile 24: Pennsylvania Duplexii
author = Brian Reed
year = 1972
month = June
publisher = Profile Publications
location = Windsor, Berkshire, UK] cite book
title = Classic Power 5: Pennsy Q Class
author = Harley, E.T.
year = 1982
publisher = N.J. International
location = Hicksville, New York
id = ISBN 0-934088-09-8]

They were the largest non-articulated locomotives ever built and the most powerful locomotives ever static tested, producing 7,987 hp (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 With dieselization, they were the obvious first targets to be withdrawn since they were only a little more capable than the conventional J1 class 2-10-4s but with far higher operating and maintenance costs.

References

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