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 I1s2-10-0 "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.
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.
K5 #5698 was built at the PRR's Juniata Works (Juniata 4205 / 1929) in 1929, but having a works plateAltoona Works 4205 / 1929. This according to late Mr Ivan W. Saunders, Pittsburgh, Pa. A one-piece cast steel locomotive bed was used; this produced the locomotive frame, cylinders, and smokebox saddle as one giant steel casting. This casting was produced by Commonwealth Steel's Granite City, Illinois plant. This cast locomotive bed design was a successful trial, and was repeated on 1930s order for 100 M1a class 4-8-2 "Mountains", as was the Worthington feedwater heater with mixing chamber behind the stack.
During the New York World’s Fair of 1939-40, K5 5698 was displayed along with several other PRR locomotives at the fair. In 1941, following the fair, 5698 was modified with a smokebox extension and a different feedwater heater within.
5698 was again modified by 1948 with a new (one-piece) smoke box, new cylinders with outside steam pipes, and “modern” front end.
Baldwin-built #5699
In contrast, Baldwin-built #5699 (Baldwin 60660 / 1928) used a conventional, fabricated locomotive frame, longer smokebox with the feedwater mixing chamber in front of the stack and the generator mounted on the right side (below the stack), and separate cylinder plus half-saddle castings. The innovation trialled on #5699 was its use of Caprotti valve gear, a poppet valve gear invented in Italy. The greater efficiencies of this gear gave the locomotive a higher tractive effort of 58,092 lbf (258.41 kN).
Although efficient, the Caprotti gear proved less reliable than the regular Walschaerts valve gear and required more frequent, more skilled maintenance, and in 1937 it was replaced by Walschaerts gear driving regular piston valves, making the two locomotives (except for frames) functionally identical.
Service life
The two locomotives were originally assigned to haul Philadelphia to Pittsburgh through trains. After the electrification reached Harrisburg, they were reassigned to the twisting Harrisburg–Baltimore route. Finally, they were reassigned to Pittsburgh–Crestline trains.
Both were updated after World War 2 with the standard front-end "beauty treatment" given to most K4s locomotives: a sheet-steel drop coupler pilot, higher-mounted headlight, and turbo-generator mounted on the smokebox front for easier access. They lost their unique bell placement at this time for a location equally unique for the PRR: under the generator-service platform on the front of the smokebox.
Conclusion
Like many experimental locomotives, the K5 was only a qualified success. Both locomotives performed well enough to be kept in service, but they did not perform so outstandingly as to persuade the PRR to build more. They proved that building a larger Pacific than the K4s was not worthwhile; the reduced factor of adhesion limited the locomotives' ability to put their greater power to full use. A larger locomotive with eight driving wheels was needed.
This route was eventually taken, although in striking form with the T14-4-4-4duplex locomotive, but the Great Depression and the huge cost of electrification meant that PRR steam locomotive development effectively ceased after the K5 and M1a. The electrical department became the thrust of PRR locomotive policy, and the displaced steam locomotives from electrified territory gave the PRR a surplus of locomotives, giving little incentive to develop more.
The cast steel locomotive bed and Worthington feedwater heater both proved themselves, and they became a feature of most PRR steam locomotives built after the K5, and indeed those on many other railroads.
Both locomotives were scrapped.
References
December 27, 2022
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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 PRR K5Builder s photograph of Altoona built K5 5698 Type and originPower typeSteamBuilder 5698 PRR Altoona Works 5699 Baldwin Locomotive WorksSerial numberAltoona 4205Baldwin 60660Build date1929Total produced2Rebuild date1937Number rebuilt1SpecificationsConfiguration Whyte4 6 2Gauge4 ft 8 1 2 in 1 435 mm standard gaugeDriver dia 80 in 2 032 m Adhesive weight208 250 lb 94 460 kg Loco weight327 560 lb 148 580 kg Tender type130 P 75Fuel typeCoalFuel capacity22 short tons 20 0 t 19 6 long tons Water cap 12 475 US gal 47 220 l 10 388 imp gal Boiler pressure250 psi 1 7 MPa Heating surface4 285 sq ft 398 1 m2 Superheater Heating area1 634 sq ft 151 8 m2 Cylinders2Cylinder size27 in 30 in 686 mm 762 mm Valve gear 5698 Walschaerts 5699 Caprotti rebuilt to WalschaertsPerformance figuresMaximum speed80 96 MphTractive effort 5698 54 675 lbf 243 21 kN 5699 58 092 lbf 258 41 kN as builtFactor of adh 3 8CareerOperatorsPennsylvania RailroadClassK5Number in class2Numbers5698 5699Delivered1929Retired1952 1953DispositionBoth scrappedIn comparison K4s K5Cylinders 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 80The 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 1 Altoona built 5698 2 Baldwin built 5699 3 Service life 4 Conclusion 5 ReferencesAltoona built 5698 EditK5 5698 was built at the PRR s Juniata Works Juniata 4205 1929 in 1929 but having a works plate Altoona Works 4205 1929 This according to late Mr Ivan W Saunders Pittsburgh Pa A one piece cast steel locomotive bed was used this produced the locomotive frame cylinders and smokebox saddle as one giant steel casting This casting was produced by Commonwealth Steel s Granite City Illinois plant This cast locomotive bed design was a successful trial and was repeated on 1930s order for 100 M1a class 4 8 2 Mountains as was the Worthington feedwater heater with mixing chamber behind the stack K5 5698 used conventional Walschaerts valve gear and piston valves and developed a starting tractive effort of 54 675 lbf 243 21 kN During the New York World s Fair of 1939 40 K5 5698 was displayed along with several other PRR locomotives at the fair In 1941 following the fair 5698 was modified with a smokebox extension and a different feedwater heater within 5698 was again modified by 1948 with a new one piece smoke box new cylinders with outside steam pipes and modern front end Baldwin built 5699 EditIn contrast Baldwin built 5699 Baldwin 60660 1928 used a conventional fabricated locomotive frame longer smokebox with the feedwater mixing chamber in front of the stack and the generator mounted on the right side below the stack and separate cylinder plus half saddle castings The innovation trialled on 5699 was its use of Caprotti valve gear a poppet valve gear invented in Italy The greater efficiencies of this gear gave the locomotive a higher tractive effort of 58 092 lbf 258 41 kN Although efficient the Caprotti gear proved less reliable than the regular Walschaerts valve gear and required more frequent more skilled maintenance and in 1937 it was replaced by Walschaerts gear driving regular piston valves making the two locomotives except for frames functionally identical Service life EditThe two locomotives were originally assigned to haul Philadelphia to Pittsburgh through trains After the electrification reached Harrisburg they were reassigned to the twisting Harrisburg Baltimore route Finally they were reassigned to Pittsburgh Crestline trains Both were updated after World War 2 with the standard front end beauty treatment given to most K4s locomotives a sheet steel drop coupler pilot higher mounted headlight and turbo generator mounted on the smokebox front for easier access They lost their unique bell placement at this time for a location equally unique for the PRR under the generator service platform on the front of the smokebox Conclusion EditLike many experimental locomotives the K5 was only a qualified success Both locomotives performed well enough to be kept in service but they did not perform so outstandingly as to persuade the PRR to build more They proved that building a larger Pacific than the K4s was not worthwhile the reduced factor of adhesion limited the locomotives ability to put their greater power to full use A larger locomotive with eight driving wheels was needed This route was eventually taken although in striking form with the T1 4 4 4 4 duplex locomotive but the Great Depression and the huge cost of electrification meant that PRR steam locomotive development effectively ceased after the K5 and M1a The electrical department became the thrust of PRR locomotive policy and the displaced steam locomotives from electrified territory gave the PRR a surplus of locomotives giving little incentive to develop more The cast steel locomotive bed and Worthington feedwater heater both proved themselves and they became a feature of most PRR steam locomotives built after the K5 and indeed those on many other railroads Both locomotives were scrapped References Edit Retrieved from https en wikipedia org w index php title Pennsylvania Railroad class K5 amp oldid 1125919360, wikipedia, wiki, book, books, library,
