Pennsy Steam Locomotives

Class A	0-4-0	The PRR was the last holdout of the 0-4-0 type on a large American railroad, thanks to its miles of cramped industrial sidings.
A3		84 class A3 locomotives were built 1895-1905. Used on light and tightly curved trackage where larger shifters could not venture; streets, docks, industrial sidings. The last A3s were retired in the 1930s, replaced by the slightly larger A5.
A3a		A small number of A3 locomotives were given saddle tanks and small coal bunkers to act as workshop 'goats'. Their short length enabled them to fit on turntables, transfer tables etc. with the dead locomotive they were moving.
Class B	0-6-0	The 0-6-0 was the PRR's standard switcher type.
B6sb		The B6 was the PRR's standard 0-6-0 shifter. More than 350 of all subclasses were built; this B6sb was the ultimate version, with superheat, piston valves and power reverse; 238 of this subclass were constructed.
Class C	0-8-0	The 0-8-0 did not find favor on the PRR, although other roads liked them.
C1		90 class C1 were built for the PRR in 1925-1927. The largest two-cylinder 0-8-0s built anywhere, they did not prove successful, Consolidation (2-8-0) locomotives being preferred.
Class D	4-4-0 "American"	The pre-eminent passenger locomotive of the 19th Century
D16sb		The final embodiment of the American type on the PRR, the D16sb finished its days in suburban commuter and branch line service. It was one of very few American type locomotives fitted with superheating and piston valves.
Class E	4-4-2 "Atlantic"	The Atlantic succeeded the American in passenger service
E6s		Built to equal Pacifics, the E6s was the Pennsy's flatland flyer, and with the sole exception of the Milwaukee's streamlined quartet of class A1, was the acclaimed 'Apex of the Atlantics'
Class G	4-6-0 "Ten-Wheeler"	Used in suburban commuter service
G5s (PRR)		Fast-accelerating locomotives for commuter service, these were rough-riding, brutish machines, the largest, heaviest and most powerful 4-6-0s built in America. They were, surprisingly, hand fired.
G5s (LIRR)		The Long Island Railroad was at that time owned by the PRR, and leased or owned many PRR locomotives. Thirty-one G5s locomotives were built for the LIRR, with larger tenders (similar to common ones on K4s locomotives). Two of these are preserved.
Class H	2-8-0 "Consolidation"	The Consolidation was the most numerous PRR type
H9s		The almost-identical H8, H9 and H10 Consolidations were the most common type of steam locomotive on the PRR; Consolidations made up approximately half of the PRR's total locomotives. Although replaced in heavy freight service by larger engines, Consolidations ran branchline freight, work trains, switching service, and pretty much everything else.
Class I	2-10-0 "Decapod"	Unloved on other roads, the PRR found their brute strength perfect for mountain lugging
I1s		The PRR built almost 600 of these brutishly powerful locomotives. Rough-riding, to be sure, but there was nothing a couple of these could not pull. On heavy coal trains, two on the front and two pushing from behind.
Class J	2-10-4 "Texas"	The largest two-cylinder power on the PRR
J1/J1a		These "war babies" were built to a C&O design, there being no time to design from scratch in 1942. Their look was 'Pennsy-fied' by the cast pilot, smokebox door keystone, PRR style cab and sixteen-wheel PRR long distance tender, but no Belpaire firebox showed their non-PRR origins. 125 were built and they were appreciated as among the best ever.
Class K	4-6-2 "Pacific"	The PRR relied on Pacifics until the end
K4s		The K4s was the biggest class of Pacifics in America, numbering 425 examples, and one of the best known. Unlike most other roads, the PRR ran most trains with Pacifics until dieselization.
K4s (streamlined)		Most roads experimented with streamlining, and the PRR was no exception. K4s #3768 received this rather bulbous shroud to pull the Broadway Limited in the 1930s, designed by the industrial designer Raymond Loewy. The locomotive was initially painted a bronze color, as depicted here.
Class L	2-8-2 "Mikado"	Numerous, but underappreciated
L1s		The freight sibling of the K4s with the same boiler, cab and trailing truck, 574 L1s locomotives were built 1914-1919, their construction rushed to meet First World War traffic demands. Outclassed very soon by larger power, they were put onto secondary duties.
Class M	4-8-2 "Mountain"	The Pennsy's fast freight haulers
M1		Built as dual purpose locomotives, the M1 found its niche in fast, time-sensitive freight service. Possessing both power and speed, the M1 was generally considered the PRR's best steam locomotive.
M1a		The M1a had a one-piece casting for the cylinders and smokebox saddle with inside steam delivery pipes, and a Worthington feedwater heater with the mixing chamber behind the stack. Twin air compressors were fitted. In later years some were rebuilt into class M1b with higher steam pressure and firebox circulators.
Class Q	4-6-4-4 or 4-4-6-4	Duplex freight locomotives
Q1 Early		The 1942-built Q1 was the PRR's first freight Duplex prototype. Oddly, considering its freight role, it was built with large 77" drivers and streamlining. The rear pair of cylinders were mounted alongside the firebox, driving the rear two pairs of wheels; this proved to be a poor location.
Q1 Late		In 1945, the sole Q1 was partially destreamlined. The nosecone and side skirting were removed, although the skyline casing was retained. In this form the Q1 remained until its scrapping.
Q2		The lessons learned with the Q1 influenced the building of the prototype Q2 #6131 and the 25 production locomotives. The cylinders were built the conventional way round, and the drivers a more normal size (69") for a freight locomotive. Apart from high maintenance costs, the Q2 proved relatively successful, with one of the highest recorded horsepower outputs of any locomotive anywhere.
Class T	4-4-4-4	Duplex passenger locomotives
T1		This is #6110, the prototype T1. With a Raymond Loewy-designed sharknose shroud that cannot be described as pretty, but certainly was distinctive, the T1 certainly looked revolutionary. Unfortunately it proved prone to slipping, and expensive to maintain, although it was capable of legendary performance in skilled hands.