The Juniata Shops in Altoona, PA began constructing 4-6-2 locomotives in 1910 and by 1911 had built 153 very similar copies of the ALCO built "Pacific" bought in 1907. These locomotives were designated as Class K-2 and were assigned road numbers scattered from 23 through 9999. They had 80" drivers, 24 x 26 cylinders, a boiler pressure of 205 psi, exerted 32,620 lbs of tractive effort, and weighed 278,800 lbs with 185,900 lbs on the drivers. The tenders carried 7,100 gallons of water and 16 tons of coal. There was a "ghost" class K-1, a design which had a smaller boiler and lower pressure than the Class K-28. The K-1 design was rejected without a single example being built.
A slight modification was made to the design of the Class K-2, in late 1911, the firing deck was raised to accommodate stokers. The Juniata Shops produced 62 of these modified locomotive which were designated as Class K-2a, between 1911 and 1913. ALCO was given an order and delivered 10 of the Class K-2a locomotives in 1912. These 72 Class K-2a 4-6-2s were numbered with scattered road numbers from 86 through 8543. Though designed to have stokers only a few were actually installed.
Another two "Pacific" were built in 1911. They were very similar to the Class K-2 locomotives except they had 72" drivers. This pair was designated as Class K-2b, with road numbers 3371 and 3375 assigned.
In 1913, the Baldwin Locomotive Works built 30 more "Pacifics" for the PRR. These were very similar to the Class K-2 locomotives except they had larger cylinders (26" dia.) were super heated and equipped with mechanical stokers. With the larger cylinders they exerted 38,280 lbs of tractive effort. This group was designated Class K-3s and given scattered road numbers from 7004 through 8663.
In all, 257 "Pacifics" were built based on the 1907 experimental Class K-28.
Satisfied with the performance of the Class K-29 locomotive the PRR built a similar locomotive in the Juniata Shops and it was put into service in 1914. This locomotive was given road number 1737 and was designated a Class K-4s. Number 1737 was put through an extensive testing program and was found to be an excellent locomotive. The railroad had a top priority order for 2-8-2 "Mikados" going through the Juniata Shops and the Class K-4s "Pacifics" would have to wait until 1917 before the shop could begin to build them.
Starting in 1917 and continuing through 1928 the Juniata Shops built a total of 349 of the K-4s "Pacifics" and the Baldwin Locomotive Works built 75 of them. These locomotives were given the following road numbers:
8, 12, 16, 20, 43, 122, 225, 227, 262, 269, 295, 299, 358, 359, 383, 389, 422, 452, 518, 526, 612, 623, 646, 669, 719, 830, 837, 850, 911, 920, 945, 949, 958, 962, 1120, 1139, 1188, 1195, 1329, 1330, 1339, 1361, 1392, 1395, 1433, 1435, 1436, 1453, 1462, 1488, 1497, 1517, 1522, 1526, 1531, 1533, 1546, 1551, 1554, 1588, 1653, 1737, 1980, 1981, 1983, 1984, 1985, 2032, 2034, 2112, 2445, 2665, 2673, 2761, 3654, 3655, 3667 through 3684, 3726 through 3775, 3800, 3801, 3805, 3806, 3807, 3838 through 3889, 5022, 5038, 5041, 5058, 5072, 5077, 5086, 5147, 5154, 5238, 5243, 5253, 5296, 5334 through 5399, 5400 through 5499, 7053, 7054, 7116, 7133, 7244, 7267, 7270, 7273, 7274, 7275, 7278, 7279, 7280, 7287, 7288, 7914, 7938, 8009, 8068, 8085, 8108, 8114, 8122, 8137, 8157, 8161, 8165, 8181, 8195, 8212, 8218, 8225, 8236, 8240, 8242, 8251, 8261, 8278, 8281, 8309, 8334, 8347, 8373, 8377, 8378
The Class K-4 locomotive was a splendid machine and the designed incorporated many of the outstanding features of the earlier Class E-6 "Atlantic" (4-4-2) passenger locomotive plus technology developed for the earlier "Pacifics" and the the ALCO Class K-29. Also some of the design features of the Class L1 "Mikado" (2-8-2) freight were made part of the K-4s design.
The heart of the design was its long tapered boiler with its huge square shouldered "Belpaire" firebox. The six 80" drivers were moved by light weight, hollow ground piston rods, crossheaders and nickel-chrome steel main side rods, regulated by Walschaerts valve gear.
There were eight different styles of tenders used with the Class K-4s locomotives. They ranged form the original tender with a capacity of 7,000 gallons of water and 12 1/2 tons of coal to the so-called "Coast-to-Coast" tender with its capacity of 22,090 gallons of water and 31 1/2 tons of coal. And in between some of the "Mountain" tenders were used with the K-4s. In the 1930s Mechanical Engineer W. F. Kiesel, Jr designed three new tenders for use with the K-4s. They were, the Class 90-P-75 (9,700 gallons of water and 21 tons of coal), the Class 110-P-75 (11,980 gallons of water and 18 1/2 tons of coal) and the Class 130-P-75 (13,475 gallons of water and 22 tons of water).
By the late 1930s, 75% of the earlier classes of "Pacifics" had been scrapped, but only one of the K-4s locomotives had been lost. Number 8309 derailed in Pittsburgh, PA on December 27, 1937. and it fell off a cliff and was damaged beyond repair. It would be almost ten more years before another one of the K-4s would be retired. So it was the remaining 424, Class K-4s "Pacifics" (and the GG1s) that were the work horses that pull most of the passenger trains during railroads busiest decade, the 1940s,
The Pennsylvania Railroad often referred to itself as the "Standard Railroad of the World" and to millions of rail travelers, millions of servicemen during World War II, and railfans for over 80 years, the Class K-4s was, and to many still is, the "Standard Passenger Locomotive".
Later, in 1940 and 1941 four more K-4s locomotives received a streamlined shroud. This shroud was of a more simple design as compared to the 1936, Loewy design. The four were road numbers: 1120, 2665, 3678, and 5338. Eventually, all five of the streamed locomotives had their shrouds removed were restored to their original appearance. Another locomotive, number 1188, did not get a full streamline shroud, but did get a boiler top cowling and was dubbed "The Skyline".
Raymond Lowey not only designed the shroud of the K4, he wrote a book about it and compared it to European and American streamlining efforts. He claims his PRR commissions were the "epitomy of streamline theory". If you are talking electric locomotives, then Raymond Lowey is probably right, since he did style the carbody of the GG1, but nobody thinks his K-4 is close to the New York Central's J-3 in terms of beauty. In fact, the PRR's streamlined locomotives were downright ugly, with the possible exception of the T-1, a 4-4-4-4 which looked a lot better than it performed.
Number 5436 was fitted with steam actuated valves designed by the Altoona Works Engineer of Tests, Lloyd Jones. The valves were installed in 1940. In 1945, another K-4s, number 3847 was equipped with a front end throttle and Franklin rotary-actuated poppet valves. All of the poppet valve applications did a good job especially at higher speeds. However, they were difficult to maintain.
On the Vandalia, they were Class VK1, road numbers 1 through 12 and on the PRR they were designated as Class K-21 and were assigned road numbers 8701 through 8712.
The two K-5 locomotives were assigned to haul Philadelphia - Pittsburgh passenger trains and after electrification were assigned to the North Central line between Harrisburg and Baltimore.
By the time these locomotives were completely tested and evaluated the state-of-the-art had moved beyond the 4-6-2 wheel arrangement and the "Mountains" 4-8-2 were beginning to arrive and they incorporated many of the features tested in the K-5 locomotives.
Number 5698 was dropped from the roster in October, 1952 and 5699 was retired in September, 1953.
| Class | Qty | Road Numbers | Year Built | Builder |
|---|---|---|---|---|
| K-28 | 1 | 7067 | 1907 | ALCO |
| K-2 | 83 | 23, 77, 150, 163, 247, 347, 382, 397, 482, 654, 732, 821, 838, 927, 997, 1061, 1119, 1184, 1246, 1253, 1396, 1458, 1525, 2125, 2437, 2980, 3250, 3251, 3320 through 3327, 6621, 6625, 7048, 7114, 7137, 7153, 7175, 7202, 7510 through 7528, 8635 through 8644, 9990 through 9999 | 1910 | PRR |
| K-2 | 70 | 748, 922, 1088, 1245, 3328 through 3338, 3344 through 3370, 3372, 3373, 3374, 3376 through 3394, 5035, 5060, 5107, 5130, 5133, 5191 | 1911 | PRR |
| K-29 | 1 | 3395 | 1911 | ALCO |
| K-2b | 2 | 3371 & 3375 | 1911 | PRR |
| K-2a | 3 | 86, 238 & 877 | 1911 | PRR |
| K-2a | 52 | 170, 196, 849, 1372, 1628, 1630, 1635, 3402 through 3411, 4096, 5014, 5039, 5078, 5087, 5097, 5112, 5183, 5212, 5214, 5221, 5223, 6064, 6084, 6085, 7170, 7177, 7182, 7183, 7211, 7217, 7219, 7224, 7271, 7272, 7316, 7319, 7327, 8077, 8111, 8395, 8528, 8529, 8541, 8543 | 1912 | PRR |
| K-2a | 10 | 7018, 7039, 7049, 7070, 7142, 7166, 7167, 8004, 8018, 8045 | 1912 | ALCO |
| K-2a | 7 | 758, 1266, 1277, 1301, 1346, 1350, 1387 | 1913 | PRR |
| K-3s | 30 | 7004, 7012, 7075, 7079, 7149, 7161, 7187, 7301, 7308, 7337, 7546, 7547, 7548, 7549, 7791, 7792, 7793, 8091, 8154, 8232, 8238, 8391, 8656 through 8663 | 1913 | Baldwin |
| K-4s | 1 | 1737 | 1914 | PRR |
| K-4s | 41 | 12, 20, 43, 122, 227, 299, 358, 359, 383, 389, 422, 612, 623, 669, 719, 830, 920, 1120, 1139, 1188, 1195, 1395, 1453, 1462, 1488, 1497, 2034, 2445, 5022, 5038, 5041, 5058, 5072, 5077, 5086, 5147, 5154, 5238, 5243, 5253, 5296 | 1917 | PRR |
| K-4s | 111 | 8, 16, 225, 262, 269, 295, 452, 518, 526, 646, 837, 850, 911, 945, 949, 958, 962, 1329, 1330, 1339, 1361, 1392, 1433, 1435, 1436, 1517, 1522, 1526, 1531, 1533, 1546, 1551, 1554, 1588, 1653, 1980, 1981, 1983, 1984, 1985, 2032, 2112, 2665, 2673, 2761, 3654, 3655, 3667 through 3684, 5334 through 5349, 7053, 7054, 7116, 7133, 7244, 7914, 7938, 8009, 8085, 8157, 8161, 8165, 8181, 8195, 8212, 8218, 8225, 8236, 8240, 8242, 8251, 8261, 8278, 8281, 8309, 8334, 8347, 8373, 8377, 8378 | 1918 | PRR |
| K-4s | 15 | 7267, 7270, 7273, 7274, 7275, 7278, 7279, 7280, 7287, 7288, 8068, 8108, 8114, 8122, 8137 | 1919 | PRR |
| K-4s | 50 | 3726 - 3775 | 1920 | PRR |
| K-4s | 57 | 3800, 3801, 3805, 3806, 3807, 3838 through 3889 | 1923 | PRR |
| K-4s | 50 | 5350 - 5399 | 1924 | PRR |
| K-4s | 75 | 5400 - 5474 | 1927 | Baldwin |
| K-4s | 17 | 5475 - 5491 | 1927 | PRR |
| K-4s | 8 | 5492 - 5499 | 1928 | PRR |
| K-5 | 1 | 5698 | 1929 | PRR |
| K-5 | 1 | 5699 | 1929 | Baldwin |
| K-21 | 12 | 8701 - 8712 | 1911-12 | From the Vandalia in 1917 |
In 1988, number 1361 was returned to the Juniata Shops for assessment of the damage. At this time, the Federal Railroad Administration became more active in regulating operation of historic steam locomotives. Frequently changing regulations and the extent of the damage caused a great debate as to how to proceed with the restoration.
After raising funds, the Museum signed a contract, in 1994, with the University of Scranton and Steamtown for work to restore the locomotive. The University is to provide the project management and Steamtown is to provide shop space, equipment and labor. In the Spring of 1996, it was moved to Steamtown where work began the following year.
The work has progressed, but there is still more to do. In early 1999, the Museum needed to raise about $500,000.00 to finish the project. Donations can be made by contacting The Railroader's Memorial Museum at 814-946-0834.
The impostor, number 1737, was sent to Northumberland where it was put into storage for ten years. In 1968, it was sent to the new Railroad Museum of Pennsylvania which was amassing its collection and it was on display in the museum's train yard when it opened in 1976.
By 1983, continued exposure to the elements had taken its toll on the locomotive and it was sadly in need of repair. In June, 1983, a crew of volunteers from an organization known as Friends of the Railroad Museum began a cosmetic refurbishment of the locomotive. After several months of work and after the new coat of Brunswick green paint had dried the locomotive was given its original number and is now on display as number 3750.
On December 18, 1987, Pennsylvania's governor Robert Casey signed a bill naming the PRR's K-4s the "Official State Locomotive". This title is applied equally to both the surviving Class K-4s locomotives, number 1361 and number 3750.
This was a single Lines West "Alco", but unlike the K29, which remained unique, this engine led to Pennsy's own K2 design. The grate was quite large, the piston valves relatively enormous at 16"(406 mm) diameter and 7" (279 mm) stroke, and the firebox radially stayed, but otherwise the K2s followed easily from this prototype.
Later superheated and redesignated K28s, when it had very nearly the same number of tubes and flues (200 & 30, vs 202 and 32) as the K2s.
Retirement and scrapping came in June 1933.
Drury (1993) observes that "At some point Alco must have realized that even if it built an engine PRR would buy a thousand [examples] of, Baldwin and Juniata would split the order." Even so, Edson (Keystone Steam & Electric, 1974) observes, the Alco K29 in many ways served as the forerunner for the K4 absent the Belpaire boiler.
This lone wolf soldiered on until 1929.
This is an umbrella classification for several K2 classes that soon acquired identical dimensions and power. 151 K2a were converted to K2s, and the 72 K2a that were built by Alco and Altoona from 1911-1913 were soon converted to K2sa. 72 K2sa were built from 1910-1913, all but 10 (Alco) built by Juniata. All had Belpaire fireboxes. Most superheated within a few years of completion. Some built with mechanical stoker (later removed).
Edson (Keystone Steam & Electric, 1974) notes that the K2 design was prepared by Fort Wayne while Altoona designed its K1. The K1 was not produced.
Very few of this class survived the 1930s, most being retired early in that decade.
Interim design between much more numerous K2 (225 built) and K4 (425 built). Intended for the Lines West routes, the K3 used the same boiler and Belpaire firebox as the K2sa, but the cylinder diameter grew by 2 inches, squaring the cylinder-stroke dimension. K3s also were delivered with a mechanical stoker, which apparently was acceptable west of Pittsburgh, but not in those areas ruled by Altoona.
One of the K3 engines delivered in July 1913 was Baldwin's 40,000th locomotive. Road numbers ranged from 7004 to 8663. The Pennsy sold five of the class in October 1930--works 39730, 39764, 39792, 39952-39553--to the Norfolk & Western, which operated them as class E-3 (road numbers 500-504).
425 K-4s entered service -- 350 constructed at Juniata and 75 at Baldwin. 1924-1928 locomotives numbered from 5350 to 5499, the Baldwin locos numbering 5400 to 5474. The Baldwin batch engine weight was 308,890 lb. The piston load per pound of reciprocating parts was 87 lb, according to Railway Age (21 July 1916), which was 4.8% more than the E6 Atlantics, and 10.1% more than the Reading Pacifics.
The K-4 prototype generated 3,184 hp for 60 minutes running at 200-240 rpm (48-57 mph) and 60% cut-off. Other tests showed 1,275 indicated HP at 67 mph at 15% cut-off, 2,355 hp at 35% cut-off. Robert Tufnell (The Illustrated Encyclopedia of Railway Locomotives (London: Quarto Publishing Ltd, 1986)) notes that at the most efficient steaming rate of 34,000 lb/hour, boiler efficiency was 76% and the engine burned fuel at the rate of 1.8 lb/ihp/hour (5,800 lb/hour).
As with most Pennsy locomotives, the K-4 had a Belpaire firebox. (See Locobase 32 for a comment on the unique design of Pennsy's Belpaire firebox.) Power reversing gear was fitted to the class in the 1920s and most received a mechanical stoker in the 1930s.
Sources differ on the size of the superheater with a couple of the diagrams reproduced by Schoenberg noting areas of 1,072 and 1,157 sq ft. But the majority of diagrams from all periods of K-4 service show the 943 sq ft (305 sq ft of firebox area) recorded in the specs.
The tender weight represents the larger tender. Smaller ones held 7,250 gallons of water and 13 1/2 tons of coal. Most K4s were hand-fired, which is often highlighted as backward thinking. See, however, John W Orr's excellent account of an engineer on the Pennsy (Set Up Running, published by PSU Press in 2001) in which he describes on pp. 116-117 the "bank-firing" technique used by a fireman on a K4. After laying the bed in an orthodox pattern, the fireman piled large amounts of coal, "especially in the corners", but left a bright fire in the middle. Stoking the fire during the K4s high-speed runs consisted of placing a few shovelsful of new coal in the bright fire patch, which kept the pressure at near pop-off point.
5698 was built by Juniata with Walschaerts valve gear; called the General Butler. 5699 built by Baldwin with Caprotti poppet valve gear and called the Mussolini (because of its "Italian" valve gear). Both were fitted with a Worthington "PRR" Special Type S feedwater heater.
These were hand-bombers with a GDF that suggests the Herculean task facing the fireman. See Locobase 159 for a description of the "bank-firing" technique that saved the shoveller's back. The Caprotti gear on 5699 was later replaced by Walschaerts radial valve gear.
Not considered a success.
According to the notes in Bob Berkey's PRR Steam Locomotive Classification, the specs for these Indiana engines were similar to the Pennsy's K-2 and K-3 designs, but they were lighter, used a radial-stay firebox, and a different kind of trailing truck. They had 14" diameter piston valves. The first group was delivered with saturated boilers containing 383 2" tubes.
The Pennsy took them over in 1917 and scrapped them from December 1929-August 1930. One suspects the short lifetime is attributable to the relatively modest power dimensions and the small number of engines. This assessment is reinforced by an October 1910 account in Railway & Locomotive Engineering (p. 382) that emphasizes the easy gradients and wide-sweeping curves over which the Vandalia's trains had to travel. Perhaps when it came time to put them to more demanding use, the railroad found these locomotives would not serve.
| Specifications by Steve Llanso | |||||||
|---|---|---|---|---|---|---|---|
| Class | K28 | K29 | K2sa | K3s | K4s | K5 | VK1 / K21s |
| Locobase ID | 5693 | 7581 | 161 | 162 | 159 | 160 | 7587 |
| Railroad | Pennsylvania (PRR) | Pennsylvania (PRR) | Pennsylvania (PRR) | Pennsylvania (PRR) | Pennsylvania (PRR) | Pennsylvania (PRR) | Vandalia Lines (PRR) |
| Whyte | 4-6-2 | 4-6-2 | 4-6-2 | 4-6-2 | 4-6-2 | 4-6-2 | 4-6-2 |
| Road Numbers | 7067 | 3395 | 10000 | 7004+ | 10000 | 1-12 / 8701-8712 | |
| Gauge | Std | Std | Std | Std | Std | Std | Std |
| Builder | Alco-Pittsburgh | Alco | Juniata | Baldwin | Several | Several | Alco-Schenectady |
| Year | 1907 | 1911 | 1910 | 1913 | 1914 | 1929 | 1910 |
| Valve Gear | Walschaert | Walschaert | Walschaert | Walschaert | Walschaert | various | Walschaert |
| Locomotive Length and Weight | |||||||
| Driver Wheelbase | 13.83' | 13.83' | 13.83' | 13.83' | 13.83' | 13.83' | 13.83' |
| Engine Wheelbase | 35.16' | 36.42' | 35.20' | 35.21' | 36.17' | 36.87' | 34.71' |
| Ratio of driving wheelbase to overall engine wheebase | 0.39 | 0.38 | 0.39 | 0.39 | 0.38 | 0.38 | 0.40 |
| Overall Wheelbase (engine & tender) | 67.06' | 71.48' | 70.42' | 78.87' | 65.85' | ||
| Axle Loading (Maximum Weight per Axle) | 57675 lbs | 65000 lbs | 65000 lbs | ||||
| Weight on Drivers | 183900 lbs | 197800 lbs | 191000 lbs | 189500 lbs | 199500 lbs | 207675 lbs | 165000 lbs |
| Engine Weight | 272500 lbs | 317000 lbs | 297000 lbs | 293200 lbs | 304500 lbs | 327560 lbs | 260000 lbs |
| Tender Light Weight | 143800 lbs | 175700 lbs | 170200 lbs | 271200 lbs | 212725 lbs | 248400 lbs | 147400 lbs |
| Total Engine and Tender Weight | 416300 lbs | 492700 lbs | 467200 lbs | 564400 lbs | 517225 lbs | 575960 lbs | 407400 lbs |
| Tender Water Capacity | 7000 gals | 8280 gals | 6800 gals | 15000 gals | 12150 gals | 13475 gals | 7500 gals |
| Tender Fuel Capacity (oil/coal) | 11 tons | 13.5 tons | 16.1 tons | 24 tons | 18 tons | 22 tons | 12 tons |
| Minimum weight of rail (calculated) on which locomotive could run | 102 lb/yard | 110 lb/yard | 106 lb/yard | 105 lb/yard | 111 lb/yard | 115 lb/yard | 92 lb/yard |
| Geometry Relating to Tractive Effort | |||||||
| Driver Diameter | 80" | 80" | 80" | 80" | 80" | 80" | 80" |
| Boiler Pressure | 205 psi | 200 psi | 205 psi | 205 psi | 205 psi | 250 psi | 200 psi |
| Cylinders (dia x stroke) | 24" x 26" | 27" x 28" | 24" x 26" | 26" x 26" | 27" x 28" | 27" x 30" | 24" x 26" |
| Tractive Effort | 32620 lbs | 43376 lbs | 32620 lbs | 38283 lbs | 44460 lbs | 58092 lbs | 31824 lbs |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 5.64 | 4.56 | 5.86 | 4.95 | 4.49 | 3.57 | 5.18 |
| Heating Ability | |||||||
| Firebox Area | 205 sq. ft | 253 sq. ft | 220 sq. ft | 226.80 sq. ft | 305 sq. ft | 305 sq. ft | 221 sq. ft |
| Grate Area | 61.86 sq. ft | 66.10 sq. ft | 55.37 sq. ft | 55.40 sq. ft | 70 sq. ft | 70 sq. ft | 55.60 sq. ft |
| Evaporative Heating Surface | 4427 sq. ft | 4625 sq. ft | 3691 sq. ft | 3680 sq. ft | 4041 sq. ft | 4285 sq. ft | 3654 sq. ft |
| Superheating Surface | 988 sq. ft | 791 sq. ft | 845 sq. ft | 943 sq. ft | 1634 sq. ft | 752 sq. ft | |
| Combined Heating Surface | 4427 sq. ft | 5613 sq. ft | 4482 sq. ft | 4525 sq. ft | 4984 sq. ft | 5919 sq. ft | 4406 sq. ft |
| Evaporative Heating Surface/Cylinder Volume | 325.19 | 249.26 | 271.13 | 230.33 | 217.78 | 215.54 | 268.41 |
| Computations Relating to Power Output (More Information) | |||||||
| Robert LeMassena's Power Computation | 12681 | 13220 | 11351 | 11357 | 14350 | 17500 | 11120 |
| Same as above plus superheater percentage | 12681 | 15600 | 13394 | 13515 | 17077 | 22400 | 13010 |
| Same as above but substitute firebox area for grate area | 42025 | 59708 | 53218 | 55328 | 74405 | 97600 | 51714 |
| Power L1 | 10947 | 21244 | 23913 | 21246 | 20701 | 34399 | 22579 |
| Power MT | 393.70 | 710.34 | 828.05 | 741.52 | 686.28 | 1095.51 | 905.06 |