Re: (erielack) Photos of 2602

["J. Henry Priebe Jr." <root_@_net.bluemoon.net>]

On Fri, 11 Aug 2006, William Shultz wrote:

> Philip,
> 
> Duplex no, triplex yes. The L1s were Mallet (say that with a French 
> accent please) articulated compound locomotives. Duplex to the best of 
> my knowledge in locomotive terms, was only applied to the Pennsy's Q 
> class and T class, rigid frame locomotives.

Somewhat off topic, but as the Erie had Triplexes I think it is worth noting
the distinction between rigid framed Duplexes and the articulated framed
Triplex design.

PRR had two Q subclasses, a single 4-6-4-4 Q1 and 26 4-4-6-4 Q2's. The rear
cylinders on the Q1 were behind the rear pair of drivers facing backwards. The
Q2 had its second pair of cylinders in front of the rear drivers like a normal 
articulated layout. The Q1's rear cylinder arrangement limited the firebox
size and steam distribution was poor due to the long feed pipes for the rear
engine. I also read somewhere that the dirty firebox area was hard on the rear
cylinders. The Q2 was a much more successful design (with almost 8,000 HP in
static testing!), but rapid dieselization by the Pennsy started in 1947 and
the Q2's only lasted until 1951.

Pennsy also had the S1 6-4-4-6 Duplex. It was a 1939 monster weighing over a
million pounds. It was designed to haul 1,200 ton passenger trains at or over
100 MPH, but was too big to operate over most of the PRR system so it spent
most of its relatively short life running between Chicago to Crestline, OH. It
was displayed at the 1939 NYC World's Fair on a stationary treadmill. It must
have been quite a site with those big drivers and rods thrashing around while
the loco stood still. Some people thiunk it was the fastest steam loco over
built. PRR folks called it "The Big Engine."

Don't forget B&O 5600, the George H. Emerson. It was a 4-4-4-4 Duplex with its
cylinders on either side of the drivers like Pennsy's Q1. It was also  
displayed at the 1939 World's Fair in NYC. It only lasted about 4 years, it
was probably scrapped for the war effort. I imagine it suffered from the same
rear engine problems as Pennsy's Q1.

Henry

J. Henry Priebe Jr.    Blue Moon Internet Corp Network Administrator
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