k-4's k-5's

[indian_hills_r_r]

can anyone be kind enough to explain the difference between a penn k-4   k-5?

[RAM]

The Pennsylvania Railroad's class K5 was an experimental 4-6-2 "Pacific" type, built in 1929 to see if a larger Pacific than the standard K4s was worthwhile. Two prototypes were built, #5698 at the PRR's own Altoona Works, and #5699 by the Baldwin Locomotive Works. Although classified identically, the two locomotives differed in many aspects, as detailed below. They were both fitted with a much fatter boiler than the K4s, but dimensionally similar to those of the I1s 2-10-0 "Decapods". Most other dimensions were enlarged over the K4s as well; the exceptions being the 70 square feet (6.5 m2) grate area and the 80 in (2.032 m) drivers.

In comparison:
   K4s    K5
Cylinders    27 in × 28 in (686 mm × 711 mm)    27 in × 30 in (686 mm × 762 mm))
Boiler pressure    205 psi (1.41 MPa)    250 psi (1.7 MPa)
Total heating surface    4,041 square feet (375.4 m2)    4,285 square feet (398.1 m2)
Superheating surface    943 square feet (87.6 m2)    1,634 square feet (151.8 m2)
Weight on drivers    201,830 pounds (91,550 kg)    208,250 pounds (94,460 kg)
Total weight    308,890 pounds (140,110 kg)    327,560 pounds (148,580 kg)
Tractive effort    44,460 lbf (197.8 kN)    54,675 lbf (243.21 kN)
Factor of adhesion    4.54    3.80

The K5's factor of adhesion was much worse than the K4s'. This is because the K5 was more powerful than the K4s but with little more weight on drivers (and thus adhesion). Factors of adhesion below 4 are often considered undesirable for steam locomotives, and the K5 design did prove to be rather less sure-footed because of it. For this reason, 4-8-2 "Mountain" and 4-8-4 "Northern" designs with more drivers (and thus a greater allowable weight on drivers within the same axle load limit) were generally considered preferable for locomotives as powerful as the K5.

Both K5 locomotives were given a 130-P-75 tender carrying 12,475 US gal (47,220 L; 10,388 imp gal) of water and 22 short tons (20.0 t; 19.6 long tons) of coal. Surprisingly for such large locomotives built at such a late date, both were equipped for hand firing. Both were fitted with Worthington-pattern feedwater heaters, power reverse, unflanged main drivers, and both used nickel steel boiler shells. As built, both carried their bell on the smokebox front, hung below the headlight; this arrangement was common on other roads but at the time unique on the PRR.

Contents

[RAM]

Pennsylvania Railroad K4s PRR-K4s-Aberdeen.jpg
A K4s-hauled train pauses at Aberdeen, Maryland on 1944-04-26. This is the classic prewar K4s configuration.
[hide]Type and origin
Power type    Steam
Builder    PRR Juniata Shops (350), Baldwin Locomotive Works (75)
Total produced    425
[hide]Specifications
Configuration:
   ​
• Whyte    4-6-2
Gauge    4 ft 8 1⁄2 in (1,435 mm)
Driver dia.    80 in (2,032 mm)
Length    83 ft 6 in (25.45 m)
Adhesive weight    201,830 lb (91,550 kg; 91.55 t)
Loco weight    308,890 lb (140,110 kg; 140.11 t)
Total weight    468,000 lb (212,000 kg; 212 t)
Fuel type    Coal
Fuel capacity    32,000 lb (15,000 kg; 15 t)
Water cap    7,000 US gal (26,000 l; 5,800 imp gal)
Firebox:
• Firegrate area    69.89 sq ft (6.493 m2)
Boiler pressure    205 psi (1.41 MPa)
Cylinders    Two
Cylinder size    27 in × 28 in (686 mm × 711 mm)
[hide]Performance figures
Tractive effort    44,460 lbf (197.8 kN)
Factor of adh.    4.54
[hide]Career
Preserved    1361 and 3750

[ebtnut]

At least one of the K-5's spent a lot of time on the Northern Central line from Baltimore to Harrisburg.  I suspect that part of the decision on whether to build more of them or not was determined when the great Depression hit.  A lot of locos went in dead storage in the 1930's, so there was no real need for any more passenger locos.  When the economy started perking up in the late '30's the Pennsy was well into dual drive designs - T-1's, the Q-1 and the Q-2's, plus the S-1 turbine. 

[RAM]

The reason no more were built was the fact that the K4 was a better locomotive.  One big mistake Penn RR made was not using NW J"s blueprints and made 4-8-4s instead of the T1s.  The J's were a much better locomotive then the T1s at a lower cost.  Any way that is the way I see it.

[indian_hills_r_r]

thanks, guys. I have wondered why prr used numbers when others roads used names.

[RAM]

All railroads used class numbers or letters.  Like the Santa Fe had say 200 mikes 2-8-2 with 6 or more classes.

[ebtnut]

Most every large railroad had its own number and classification system.  The Santa Fe, for instance, simply used the number from the lead unit of a particular design series, such as the 3776 class of 4-8-4's.  The Pennsy used the letter-number system, with the letter indicating the wheel arrangement (K for 4-6-2's) and the number being the particular design (a K-4 being the fourth in the Pacific design series).  With the B&O, the alphabet letter denoted the wheel arrangement.  An E class was a 2-8-0 and the following number the particular design series (E-27).  An L class was an 0-8-0.  Articulateds used the letter designations for each engine set wheel arrangement.  Thus, an EL-3 was a 2-8-8-0.  The EM-1 was a 2-8-8-4. 

[Bill Baker]

WOW!  I feel like Ive been in a history class.  Great question and great answers.  Keep it up guys!!!

Bill

[ebtnut]

OK, some more on steam locos.  The various wheel arrangements were given generic names to help sort them out for folks who didn't know all the various classifcations of the different roads.  Sone of these names were often tied to the road that first ordered a particular type - The Consolidation (2-8-0) name came from the 1860's when several railroads consolidated into the Lehigh Valley and ordered that new wheel arrangement.  Atlantics (4-4-2) were named after the Atlantic City RR;  Pacifics came from the Missouri Pacific.  Here's a partial list of some of the more common types:

4-4-0 - American
4-6-0 - Ten-Wheeler
2-6-0 - Mogul
2-8-0 - Consolidation
2-8-2 - Mikado
4-4-2 - Atlantic
4-6-2 - Pacific
4-8-2 - Mountain
4-8-4 - Northern (or Niagra, Pocono, Greenbrier, Dixie, etc.  Long story about these various names)

[Trainman203]

Most railroad men I knew on the T&NO identified engine class by roster number series as I recall from
so many years ago.  I've also read many accounts, especially on the SP, where engine classes were called 4200's ( not AC's), 4300's (not MT's), 4400's (not GS's), etc.

The PRR probably did it different, not that familiar with it.

[ebtnut]

Yes, there is quite often a difference between "official" designations and operations parlance.  Among head-end people, use of the number reference was more accurate terminology because everyone knew exactly what was meant.  "Those 2100's couldn't get traction in a sand house, but those 2400's would pull everything out of the yard".  That sort of thing.  As for the PRR, they had a big habit of spreading loco numbers all over the place with no reference to class or type of loco. 

[Trainman203]

Post 1925 (I think), on the MP, 900 numbers could mean one of several series of 4-4-0 or one of 8 Russian 2-10-0's.  And there was only one 4000, 4000 itself, MP's only articulated, a 2-8-8-2.

[oldline2]

The reason no more were built was the fact that the K4 was a better locomotive.  One big mistake Penn RR made was not using NW J"s blueprints and made 4-8-4s instead of the T1s.  The J's were a much better locomotive then the T1s at a lower cost.  Any way that is the way I see it.

The reason only 2 K5 Pacific were built has several answers. They incorporated features that were used to build the M1 class 4-8-2's which were more useful and practical to the Pennsy than more Pacifics of any class. Also the electrification of the Washington-New York line made many K4s engines "free"for the use elsewhere. The K5 was a successful engine in it's own right but just arrived at a poor time for duplication. The K5 was a more efficient engine than the K4s but at the wrong moment in time.

As to the N&W J being a better engine than the T1 that's not even open for debate. Both were very sophisticated and high tech engines at the time The N&W J was designed for mountain railroading and while it COULD do 110 mph, as proven on Pennsy tests and occasional sprints through the Dismal Swamp area west of Norfolk, it was never intended to run at those high speeds continuously whereas the T1 was made for continuous, high speed running. Hence 80" drivers vs 70" drivers. The T1 could be slippery, as could the N&W class A 2-6-6-4, but further examination of the fleet of engines has shown evidence they weren't as bad at slipping as has been rumored all these years. The high speeds caused wheel slip to be much more dramatic than low speeds and that has somewhat created the legend of them being so difficult to handle. The PRRT&HS has had much discussion and many articles on this subject and it's there in back issues of The Keystone magazine for people to read should they desire further light on them.

The tests with the C&O T-1 and N&W J on the Pennsy and the T1 on the N&W proved they designed engines for a particular use and maybe a particular service and they usually didn't work well on another railroad or type of service. Even the type of coal could make a great runner a slug to some degree. The J didn't operate as well on the lower grade coal used by the PRR compared to the high BTU N&W coal typically burned.

There were many variables to steam locomotives that generally didn't apply to the diesels which is another reason they killed steam use and production. It's not just a cut and dried, B&W situation.

We all have our favorites and the N&W J comes out very close to the top of my list and the PRR Duplex drives are near the bottom to me just slightly above the UP Pig Boy.

oldline1