The S1 had a unique 6-4-4-6wheel arrangement, meaning that it had two pairs of cylinders, each driving two pairs of driving wheels. To achieve stability at fast passenger train speeds (above 100mph), articulation was not used. The S1 was completed on January 31, 1939, at Altoona shop, and was numbered 6100.
At 140ft 2+1⁄2in (42.74m) overall, engine and tender, the S1 was the longest reciprocating steam locomotive ever; it also had the heaviest tender (451,840lb / 205 tonnes), highest tractive effort (76,403lbf (339.86kN)) of a passenger steam engine when built and the largest driving wheels (7 feet in diameter) ever used on a locomotive with more than three driving axles. The problem of wheel slippage, along with a wheelbase that was too long for many of the rail line's curves, limited the S1's usefulness. No further S1 models were built as focus shifted to the much smaller but more practical class T1 in June 1940. Design of the 4-4-4-4 T1 and the 6-4-4-6 S1 occurred concurrently, however, the S1 was the first produced.
Construction and historical background
Industrial designer Raymond Loewy stands on the front of the S1
As early as June 1936, the management of Pennsylvania Railroad decided to build a new passenger locomotive to replace its aging K4s locomotives. They also hoped that the new S1 steam locomotive would have a performance equal to their Pennsylvania Railroad class GG1 electric engine and would be capable of hauling a 1,000-ton passenger train at 100mph.[4] A conference was held between Baldwin Locomotive Works officials and W. F. Kiesel, J. V. B. Duer and W. R. Elsey for PRR, where PRR demanded a passenger locomotive to haul 15 standard cars at 100mph on level track between Paoli and Chicago. Baldwin presented several 4-8-4 and 4-4-4-4 designs made for other railroads. However, PRR rejected the 4-8-4 design in favor of a rigid frame duplex and asked Baldwin to consider the wheel arrangement 4-4-6-4. In July 1936, PRR requested Baldwin Locomotive Works to submit a design for a 4-8-4 engine capable of handling a 2,000-ton train between Colehour and Harsimus Cove.
Two months after the conference, Baldwin Locomotive Works officials presented four designs to PRR:
a 4-4-4-4 passenger locomotive that could haul 1,200 tons but exceeded existing weight and clearance restrictions
a 4-4-4-6 passenger locomotive that could haul 1,200 tons but also exceeded limits
a 4-8-4 freight locomotive with the same weight on drivers as an M1a, which failed to meet the requirements for a 2,000-ton train
an articulated 4-6-6-4 locomotive
PRR preferred 4-4-4-4 and asked Baldwin to consider a passenger version with 6 ft 8 in drivers and a freight version with 6 ft drivers. However, the cooperation between PRR and Baldwin, which proceeded without signing any agreement or contract for the development of the new high-speed duplex engine, didn't go smoothly. Ten months after the first conference (April 1937), PRR ended Baldwin Locomotive Work's consultation and assigned the task to a consortium of Baldwin Locomotive Works, American Locomotive Company, and Lima Locomotive Works under a joint contract. T. W. Demarest headed the joint committee, General Superintendent of Motive Power in PRR's Western Region.[5]
The members of the joint committee were:
Ralph P. Johnsonn (Baldwin)
William Winterwood
H. Glaenzer (Baldwin)
Dan Ennis (American Locomotive Company)
William E. Woodard (Lima)
Samuel Allen
On 28 April 1937, PRR's Board authorized $300,000 for this experimental high-speed passenger locomotive project. The design started with a 4-4-4-4 duplex.
On 2 June 1937, PRR officially announced the development of the “Pennsylvania Type” high-speed passenger locomotive which would become Class S1. After various details were discussed and finalized, it became necessary to make changes that substantially increased the locomotive's weight. By the time the plans were finalized and approved it had evolved into a 6-4-4-6.[6]
Duplex design
The benefits of a duplex design included lighter machinery, shorter cylinder stroke, less wear, lower piston thrust, smaller more efficient cylinders, and a more stable frame than an articulated underframe; also, no hinged connection had to be maintained.[7] Reduced hammer blows on the track resulted in lower maintenance cost. Two sets of drivers with four wheels each could have lighter (as much as 25%) running gear than a locomotive with all four axles coupled together, smaller and lighter moving parts ensured less wear and tear. Baldwin's chief engineer believed that the 8-coupled, two-cylinder locomotives of the time were at or near practical limits in terms of steam flow, cylinder efficiency could be improved at high speed by getting the same power from four smaller cylinders with proportionately larger valves. Valve travel in S1's cylinder was 7-1/2 in, the lap was 1-7/8 in, the lead was 5/16 in, exhaust clearance was 0.25 in, valve diameter was 12 in.
Construction
The S1 under construction at Altoona. The smaller boiler in the photo is for a B6switcher giving a sense of scale.
The S1 was the largest passenger locomotive ever constructed, and the cast steel locomotive bed plate made by General Steel Castings was the largest single-piece casting ever made for a locomotive.[4][8] In order to negotiate sharper radius curves, S1 was equipped with lateral motion devices made by Alco on its first and third set of drivers, allowing 57.2mm (2.25 inches) of lateral play on the axles, but these proved to be inadequate. Unlike other experimental duplex engines like PRR's Class Q1 #6130 4-6-4-4, there were no flangeless wheels or blind drivers adopted on S1.
In March 1938, a Chicago and North Western class E-4 4-6-4 "Hudson" #4003 was tested by PRR at Altoona.[9] Based on the test results, PRR decided to adopt 84" drivers and a cylinder pressure of 300 psi for the S1. PRR believed that the large diameter drivers could increase the tractive effort without causing undue slipping.[4] In August 1941, PRR VP-Western Region James M. Symes, a senior official who turned against the idea of duplex engine in later years, approved the extension of stall no. 30 of the Crestline roundhouse to accommodate the S1. The stall had a connection at the back because the S1 could only be turned on a wye, but not on the roundhouse's turntable.
Timken roller bearings were equipped on the crosshead pins, all engine trucks, and drive axles as well as the tender trucks. Besides, the lightweight reciprocating parts were manufactured by Timken High Dynamic Steel and designed by Timken engineers.[10] To get enough steel between the crank and axle, the back end of each main rod was offset 1+1⁄8 inches (29mm) from the crank in the driver, so the big end made a 26-inch (660mm) circle while each side rod pin made a 28+1⁄4-inch (718mm) circle.
Boiler, steaming quality and streamlining
The boiler for the S1 was the largest built by the Pennsylvania Railroad; with 660 square feet (61m2) of direct heating surface and 500 one-inch diameter tubes, the total heating surface area of S1 was 7,746 square feet (719.6m2); it was 99.3% as massive as the boiler for Union Pacific's 4000-class "Big Boy" locomotives. In terms of drawbar horsepower, the S1 was 13% more powerful than the Big Boy, with 7,200hp (5,400kW) and 6,345hp (4,731kW) respectively.[citation needed] The large Belpaire firebox met the Pennsy's standards; its heating surface area included that supplied by seven American Arch circulators. Water passed through 5.5-inch horizontal tube met at the centerline with the other cross tube forming the bottom of the 7-inch vertical tube that sprayed the water up into the steam space above the crown sheet. The lowest set pair of tubes was forward with the side openings of the other six steadily rising toward the back.
A large Worthington 6 SA feedwater heater was fitted with a 7 SA pump to handle the enormous boiler's thirst. The six-wheel leading and trailing trucks were added, as the locomotive was too heavy for four-wheel units. The streamlinedArt Deco styled shrouding of the locomotive was designed by Raymond Loewy,[1][2] a design concept based on his earlier streamlining design for PRR K4s #3768 in 1936, for which he received U.S. Patent No. 2,128,490. Raymond Loewy conducted the wind-tunnel test by using the clay model of S1 at Guggenheim Aeronautical Laboratory for the design of its streamlined shrouding, and it was the same laboratory where he conducted testing of the streamlining of PRR K4s #3768. The design of the smoke lifting plate around the smokestack on S1 was improved based on the wind-tunnel test result from Guggenheim.[11]
Construction costs and testing
The cost of the S1 was $669,780.00, equal to $14,671,066 today,[4] which was over twice the cost of a PRR T1 4-4-4-4 (#6111 cost $310,676). No. 6100 was completed at Altoona on December 21, 1938 without the streamlined casing. On the same day, it made its first road test with two cars, running backward to Huntingdon and returned to Altoona at speeds up to 50 miles per hour (80km/h). During the run, it was stopped and checked for overhang on all tight curves. Assistant Chief of Motive Power-Locomotive Carleton K. Steins (1891-1973) noted superior riding and steaming qualities.[12] During another pre-service road test, the S1 was clocked at 73 miles per hour (117km/h) towing 90 freight cars.[13]
The S1 was displayed at the 1939 New York World's Fair with the lettering "American Railroads" (a spoof of British Railways) rather than "Pennsylvania Railroad", as 27 eastern railroads had one combined 17-acre (6.9ha) exhibit, which also included the Baltimore and Ohio class N-1.[8] To reach the Fair, the S1 took a circuitous route over the Long Island Rail Road. Many obstacles, like some of the third rail guards, had to be temporarily removed while other obstacles were passed at a crawl to reach the fairgrounds. S1 was towed (facing backward) by smaller freight engines like PRR Ils and took a round-about route to the fair site. She ran up the Bel-Del, interchanged with the Lehigh and Hudson River Railway at Belvidere and NH at Maybrook. The S1 traveled over the Poughkeepsie and Hell Gate Bridge, crossed over the Hudson River and then brought it across on the NY Connecting.[14] On March 13, 1939, the S1, lettered “American Railroads” on the tender, arrived at New York World's Fair.
At the Fair, the drive wheels operated under the locomotive's steam power[4] ran continuously on the roller platform at 60mph (97km/h) for an entire day. Film footage shows that all the wheels on S1, besides the drive wheels, were also placed on rollers powered by electricity; every time S1 started its performance by moving the drive wheels, all the wheels were rolling, including the wheels on the tender's truck.
The World's Fair was open for two seasons, from April to October each year, and was officially closed on October 27, 1940. During the five-month break between October 1939 and April 1940, No. 6100 was put back on the system for passenger service and road testing. There is photo evidence showing that the S1 was hauling the Manhattan Limited, a named train serving as an alternative to the Broadway Limited, in November 1939.[15]
Popular Mechanics described S1 as the "Pride of American Railroad" in an article in their June 1939 issue.[16] The World's Fair attracted nearly 25 million visitors, S1's first 50,000 service mile was accumulated from this fair's live steam show. After the World's Fair, the S1 was re-lettered for the Pennsylvania Railroad fleet. As one of the most important exhibits of the World's Fair, S1 was used by the PRR for various publicity purposes; her image was featured in calendars, stamps, advertisements, brochures, puzzles, etc. The American Bank Note Company issued a series of stamps[17] in 1939, published by the Eaton paper company as part of an advertising campaign. One of the stamps depicts the S1 hauling the Broadway Limited.[18]
Service history
PRR S1 #6100 hauling the Trail Blazer, PRR's premier, luxury all-coach train between New York and Chicago in Nov 1942.
The S1 began its passenger train services starting from December 1940, on the run between Chicago and Pittsburgh. On its first run out of Fort Wayne, Indiana, the crew was led by H.H. Lehman (Fireman), C.J. Wappes (Road Foreman) and Frank Ritcha (Engineer). Due to its gigantic size, the S1 had to turn on the Chicago, Burlington and Quincy Railroad's wye at Chicago before going eastbound and was unable to go through the 130lb switch (No. 8) just to the west of Pittsburgh Union Station.[19] This problem wasn't fixed until 1946 (which also prevented the PRR class T1 operating through Pittsburgh).
The S1 was so large that it could not negotiate the track clearances on most of the lines of the PRR system, in its brief service life it was restricted to the mainline between Chicago, Illinois and Crestline, Ohio (283 miles/446km). It was assigned to the Fort Wayne Division and based at the Crestline engine-house. As such, the S1 had to be turned on the wye at Crestline whenever it was in town, and suffered from repeated derailments as a result.[20] Based on photographic evidence, the S1 hauled the Broadway Limited (New York to Chicago) and Liberty Limited (Washington D.C to Chicago) in the first few months of its revenue service, and was then assigned to haul other popular, heavier and commercially successful passenger trains such as The General, The Trail Blazer and The Golden Arrow on this route.[4]
Monthly mileage reports from the Hagley Library indicated that the S1 racked up 10,388-mile (16,718km) per month, equivalent to twenty round trips between Chicago, Illinois and Crestline, Ohio, which in Aug 1941 was a very spectacular figure for an experimental engine, compared to K4s monthly average of 6,000 to 8,000mi (9,700 to 12,900km). This implied that the PRR had high regard for the S1's power and speed. The S1 helped PRR to handle the extreme busy wartime traffic until the end of WWII and paid off its high construction cost within one year. Crews liked the S1, partly because of its very smooth ride at speed. The great mass and inertia of the locomotive together with the unique, massive 6-wheel trailing truck soaked up the bumps and the surging often experienced with duplex locomotives.
Operating performance and alleged speed records
PRR S1 #6100 was seen hauling the Liberty Limited eastbound at New Freedom, PA in April 1941.
In terms of tractive effort and drawbar horsepower, the PRR S1 was the most potent reciprocating steam locomotive ever built for passenger service. Starting tractive effort calculated in the usual way (85% mean effective pressure) comes out 76,400lbf (340kN), but the engine used 70.6% limited cutoff (presumably to increase port openings at short cutoff), so the railroad claimed a correspondingly lower tractive effort.[jargon] During a test run between Chicago, Illinois and Crestline, Ohio in December 1940, the S1 managed to reach 100.97 miles per hour (162.50km/h) on level track with 1,350 tons of passenger stock behind it, which was equal to 24 postwar lightweight passenger cars.[21] In this test run, the S1 also achieved an average speed of 66 miles per hour (106km/h), which was 27% faster than the average schedule speed of the route. Some publications from Germany stated that the S1 was able to reach 120.01 miles per hour (193.14km/h) in other road tests during the late 1940s when pulling lighter load, but PRR never claimed this record. On Apr 19, 1941, during an excursion run organized by the Detroit Railroad Club, the S1 reached 105 miles per hour (169km/h) on the route between Fort Wayne and Chicago.[22]
An article "Riding the Gargantua of the Rails"[23] in the Dec 1941 Popular Mechanics Magazine cites a speed recorded by assistant road foreman Charlie Wappes of the Fort Wayne Division during the S1's test runs at 133.4 miles per hour (214.7km/h) with a train of 12 heavyweight passenger cars. There are other stories of the S1 reaching or exceeding 140 miles per hour (230km/h). In the German trade press and literature from 1945 there was a report of a record run of the S1, citing railroad officials of Interstate Commerce Commission that a speed of 141.2 miles per hour (227.2km/h) was reached when the engine was trying to make up time for a delayed westbound train, the Trail Blazer.[24]
Its high-speed capability was such that many have claimed that the S1 exceeded on multiple occasions the 126mph (203km/h) record steam locomotive speed set in 1938 by the BritishLNER locomotive 4468 Mallard. The engine was claimed to have exceeded 152mph (245km/h) on the Fort Wayne-Chicago run, as it was reported that the PRR received a fine for the feat.[citation needed]
The streamlining designer of the train Raymond Loewy himself wrote in 1979: "On a straight stretch of track without any curves for miles; I waited for the S1 to pass through at full speed. I stood on the platform and saw it coming from the distance at 120 miles per hour. It flashed by like a steel thunderbolt, the ground shaking under me, in a blast of air that almost sucked me into its whirlwind. Approximately a million pounds of locomotive were crashing through near me. I felt shaken and overwhelmed by an unforgettable feeling of power, by a sense of pride at the sight of what I had helped to create."
Detail view of the driving wheels and cylinders; note the rollers upon which the wheels rested while on display
The lack of curve compatibility led to the S1 not being used for its intended long-distance express service. Although the S1 had less than half (47%) its total weight on the driving wheels, its Factor of adhesion was still close to the much more successful PRR Q2, Santa Fe "Northern" 4-8-4s the 2900s, and the renowned N&W J class 4-8-4s. More than half of its weight was carried by the three-axle pilot (leading) and trailing trucks instead of the drivers, which left the four duplex driving axles susceptible to wheel slippage. However, during the 5+1⁄2 years service history of the S1, no serious accident occurred due to wheel slippage. The S1 served between Chicago and Crestline, Ohio for almost 5+1⁄2 years, giving it a longer career than other experimental PRR steam locomotives, such as the Q1 4-6-4-4 and S2 turbine 6-8-6.
Mitigation measures
To increase the adhesion and improve performance, PRR enlarged the sand dome on the S1. It ensured the supply of sand for steam sanding and slightly increased the axle load above the first and second set axle. The S1 was partially de-skirted in 1942 to improve the visibility of the reciprocating parts for the crews and better operation.[25] Suspension springs of the pilot truck and trailer truck were fine-tuned to straighten out the overall weight distribution to achieve better performance. Railway Historian and Author Alvin F. Staufer agrees that she (S1) was oversized and thus unable to visit most roundhouses or handle tight curves, but contends: "She was an excellent steamer and gave trouble-free service."[26]
Retirement
Based on the experience gained from the S1, PRR improved the design of the T1. A total of 52 of them were ordered from 1940 to 1945.
According to an official report from PRR dated December 1, 1945, which is now stored in The Hagley Museum and Library, No. 6100 was awaiting engine truck repairs at Crestline. It was expected to be returned in service after a few days. This is one solid proof that the S1 was still in service at least until December 1945. At the time, at least 13 T14-4-4-4s were already put into service.
The design flaws of the S1 led to only one example being produced. Before the S1 was officially put in revenue service, the PRR already ordered the T1s. Unlike its duplex sisters, the S1 didn't install any form of Poppet Valve Gear, even though it was proposed to install Franklin Type A rotary cam poppet valve gear when it was already under construction, but such proposal was rejected due to technical difficulties in 1938.[25] This decision unexpectedly prevented many issues that would have been caused by the problematic Franklin valves in the T1's service. The total service years or total service mileage of the S1 (from Nov 1939 to March 1940, Dec 1940 to May 1946) was indeed slightly longer than some of the younger T1s.
A time-book belonging to Pennsy engineman Byron Breininger from the Ft. Wayne division records a trip to Chicago on No. 6100 at 8:59 AM on May 5, 1946. This run was possibly one of its last in service, as less than two years later PRR president Martin W. Clement announced that “by May of this year (1948) we expect all of our through passenger trains west of the electrified territory to be dieselized”.[27] Preservation of the S1 was discussed inside PRR's board, but due to the deteriorating financial situation since 1946, 6100 was scrapped in 1949.[4][28] The PRR continued developing the T1 class of 4-4-4-4 duplex locomotives but wheel slip and mechanical failures also plagued the T1.
Before Pennsylvania Railroad commissioned Baldwin Locomotive Works for the T1 in 1940, it had already begun developing duplex designs for fast locomotives since 1938, including a rigid-frame 4-2-2-4 and three-cylinder 4-4-4 for lightweight trains and the preliminary design for a 4-4-4-4 for heavy trains; BLW presented these designs to several railroads, but only the PRR adopted the duplex concept.[29] In Oct 1939, when the S1 was still on display in the 1939-40 World's Fair, Baldwin placed a stock order to build a 4-4-4-4 duplex high-speed passenger locomotive as a demonstrator, with bullet nose streamlining by noted industrial designer Otto Kuhler. However before it could be built, the PRR placed an order for two locomotives of this type in July 1940. This implied that the S1 was a showpiece exclusively built for the World's Fair instead of replacing the K4s as the new prime power of the PRR. The PRR T1 was developed when the S1 was under construction or on display in the World Fair.[30]
The stylish appearance of the S1 has proved to be very popular:
The S1 was represented in a 1939 painting by railroad artist Grif Teller that appeared in the Pennsylvania Railroad's picture calendar.
The American Bank Note Company issued a series of posters published by the Eaton paper company as part of an advertising campaign in 1939, one of the posters depicts the S1 hauling the Broadway Limited
Famed artist Emmanuel Zurin's Bronze sculpture "Train futuriste," a 43 inches long sculpture which features some elements of S1's front-end styling like the bullet head, lines, and curves at the pilot and its 6-wheel trucks.
CD Album "Night Train, Classic Railroad Songs, Volume 3" by Various Artists, Published by Rounder in 1998, a painting of S1 was used on the cover of the Album.
CD Album "Black Diamond Express to Hell" by Various Artists, Published by Rev. A. W. Nix in 2006, features a perspective drawing of S1 which was used as the backbone of the cover's art design.
The Danish pop group 'Laid Back's third album 'Play It Straight,' released in 1985, features a three-quarter view of the S1's bow on its cover, albeit in a gaudy pinkish-red hue it never wore in service.
The S1 appears in the Sandman comic series, book IX.
In The Galaxy Railways, the engine for Vega Platoon, Iron Burger, is loosely based on the S1, with the 4-8-8-4 wheel arrangement used for the Union Pacific Big Boy, which was used as the basis for Big One, the engine for Sirius Platoon.
A locomotive inspired by the S1 appears in the PC game Grim Fandango as "the Number Nine," the best vehicle for travel to the eternal rest.
Solomon Islands Stamps release a set of stamp in 2017 (Neofile #SI-17212a) with S1 and other express steam locomotives from all over the world like the LNER A4 Mallard on it, S1 was placed next to the LNER Mallard.[31]
Aunt Billie's "toy trains" in the 2007 film Meet the Robinsons are loosely based on this particular locomotive design.
Engine Engine No. 9, a 34-page children’s chapter book by Edith Thacher Hurd, illustrated by Clement Hurd, published in 1940 by Lothrop, Lee & Shepard Co. of Boston, has as its main character an anthropomorphic steam locomotive. Clement Hurd’s illustrations show No. 9 to be nearly identical to a PRR class S1, except for its 4-6-2 “Pacific” wheel arrangement, making No. 9 considerably shorter than a 6-4-4-6 PRR class S1.
There are Lionel and MTH models of 6100.
The locomotive has appeared in train games like Trainz and Train Simulator Classic.
Under the Whyte notation for the classification of steam locomotives, a 2-10-4 locomotive has two leading wheels on one axle, usually in a Bissel truck, ten coupled driving wheels on five axles, and four trailing wheels on two axles, usually in a bogie. These were referred to as the Texas type in most of the United States, the Colorado type on the Burlington Route, and the Selkirk type in Canada.
Locomotive classification on the Pennsylvania Railroad took several forms. Early on, steam locomotives were given single-letter classes. As the 26 letters were quickly assigned, that scheme was abandoned for a more complex system. This was used for all of the PRR's steam locomotives, and — with the exception of the final type bought — all electric locomotives also used this scheme.
The Pennsylvania Railroad K4 was a class of 425 4-6-2 steam locomotives built between 1914 and 1928 for the PRR, where they served as the primary main line passenger steam locomotives on the entire PRR system until late 1957.
The M1 was a class of steam locomotive of the Pennsylvania Railroad (PRR). It was a class of heavy mixed-traffic locomotives of the 4-8-2 "Mountain" arrangement, which uses four pairs of driving wheels with a four-wheel guiding truck in front for stability at speed and a two-wheel trailing truck to support the large firebox needed for sustained power. Although built for both passenger and freight work, they spent most of their service lives hauling heavy high-speed freight trains. Many PRR men counted the M1 class locomotives as the best steam locomotives the railroad ever owned.
The Pennsylvania Railroad (PRR) class T1 duplex-drive 4-4-4-4 steam locomotives, introduced in 1942 with two prototypes and later in 1945-1946 with 50 production examples, were the last steam locomotives built for the PRR and arguably its most controversial. They were ambitious, technologically sophisticated, powerful, fast and distinctively streamlined by Raymond Loewy. However, they were also prone to wheelslip both when starting and at speed, in addition to being complicated to maintain and expensive to run. The PRR decided in 1948 to place diesel locomotives on all express passenger trains, leaving unanswered questions as to whether the T1's flaws were solvable, especially taking into account that the two prototypes did not have the problems inherent to the production units.
A 4-4-4-4 steam locomotive, in the Whyte notation for describing locomotive wheel arrangements, has a four-wheel leading truck, two sets of four driving wheels, and a four-wheel trailing truck. While it would be possible to make an articulated locomotive of this arrangement, the only 4-4-4-4s ever built were duplex locomotives—with two sets of cylinders driving two sets of driven wheels in one rigid frame, essentially a 4-8-4 with divided drive.
A 6-4-4-6 steam locomotive, in the Whyte notation for describing locomotive wheel arrangements, is one with six leading wheels, two sets of four driving wheels, and six trailing wheels.
The Pennsylvania Railroad's S2 class was a steam turbine locomotive designed and built in a collaborative effort by Baldwin Locomotive Works and Westinghouse Electric & Manufacturing Company, as an attempt to prolong the dominance of the steam locomotive by adapting technology that had been widely accepted in the marine industry. One was built, #6200, delivered in September 1944. The S2 was the sole example of the 6-8-6 wheel arrangement in the Whyte notation, with a six-wheel leading truck keeping the locomotive stable at speed, eight powered and coupled driving wheels, and a six-wheel trailing truck supporting the large firebox. The S2 used a direct-drive steam turbine provided by the Westinghouse Electric & Manufacturing Company, geared to the center pair of axles with the outer two axles connected by side rods; the fixed gear ratio was 18.5:1. Such design was to prevent energy loss and S2 achieved a mechanical efficiency of 97% which means only 3% of steam energy was lost within the propulsion equipment. The disadvantage of a direct-drive steam turbine was that the turbine could not operate at optimal speeds over the locomotive's entire speed range. The S2 was the largest, heaviest and fastest direct-drive turbine locomotive design ever built.
The Pennsylvania Railroad's class K5 were experimental 4-6-2 "Pacific" types, 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 wider 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.
Baldwin Locomotive Works produced several different Baldwin DR-6 models of 6-axle passenger train-hauling diesel locomotives between 1945 and 1948. The series comprised eight individual versions, all of which sold only in small numbers; across all versions, only 39 locomotives were produced. Each version was produced only for a single railroad. Many shared the same Baldwin model number, DR-6-4-2000, even though they were rather different; this was because the Baldwin model only encoded the total axles (6), the driven axles (4) and the power output. The single exception was the single unit produced for the Chicago and North Western Railway, which had a single 1,000 hp (750 kW) engine and was model number DR-6-2-1000. In the AAR wheel arrangement scheme of classification, these locomotives were of A1A-A1A and A1A-3 arrangements, respectively.
The Pennsylvania Railroad's class P5 comprised 92 mixed-traffic electric locomotives constructed 1931–1935 by the PRR, Westinghouse and General Electric. Although the original intention was that they work mainly passenger trains, the success of the GG1 locomotives meant that the P5 class were mostly used on freight. A single survivor, prototype #4700, is at the National Museum of Transportation in St Louis, Missouri.
The Pennsylvania Railroad's class R1 comprised a single prototype electric locomotive constructed in 1934 by the Baldwin Locomotive Works of Philadelphia, Pennsylvania, US, with the electrical equipment by Westinghouse.
The Pennsylvania Railroad class Q1, #6130, was a single experimental steam locomotive designed for dual service. The locomotive entered service in 1942, and retired in 1949 after accumulating a relatively low 165,000 service miles.
The Trail Blazer was a deluxe all-coach train, inaugurated between New York and Chicago via Pittsburgh, Pennsylvania on 17:25 schedule operated by the Pennsylvania Railroad. The trains departed New York City and Chicago every day at 4:30 pm and 3:00 pm, respectively, and arrived at the destination the next morning. The Trail Blazer was one of the first all-coach trains to provide premium services comparable to a Pullman train. The Trail Blazer name was first used in 1927 for the East St. Louis-Pittsburgh preferred freight VL-6.
Pennsylvania Railroad 1737 was a 4-6-2 Pacific type K4 class steam locomotive built in 1914 as the first of its class and would haul heavier passenger trains that the smaller E class 4-4-2 Atlantics could not handle such as the PRR's flagship passenger train, the Broadway Limited. In the 1930s, as the PRR had increased passenger service time tables, the trains became longer and heavier than a single K4s could handle, necessitating double-heading with a second engine. The "Standard Railroad Of The World" made attempts to replace the 1737 and its classmates with larger, more powerful classes including: K5, S1, and the T1, none of which were successful; thus, the K4s continued hauling passenger trains until the Pennsylvania Railroad replaced steam locomotives with the increasingly-popular and less-costly diesel-electric locomotives in 1957.
The Manhattan Limited was a passenger train of the Pennsylvania Railroad which served the Chicago—New York City route.
The Pennsylvania Railroad G5 is a class of 4-6-0 steam locomotives built by the PRR's Juniata Shops in the mid-late 1920s. It was designed for passenger trains, particularly on commuter lines, and became a fixture on suburban railroads until the mid-1950s.
The leading wheel or leading axle or pilot wheel of a steam locomotive is an unpowered wheel or axle located in front of the driving wheels. The axle or axles of the leading wheels are normally located on a leading truck. Leading wheels are used to help the locomotive negotiate curves and to support the front portion of the boiler.
A duplex locomotive is a steam locomotive that divides the driving force on its wheels by using two pairs of cylinders rigidly mounted to a single locomotive frame; it is not an articulated locomotive. The concept was first used in France in 1863, but was particularly developed in the early 1930s by the Baldwin Locomotive Works, the largest commercial builder of steam locomotives in North America, under the supervision of its then chief engineer, Ralph P. Johnson.
Pennsylvania Railroad 5550 is a mainline duplex drive steam locomotive under construction in the United States. With an estimated completion by 2030, the locomotive will become the 53rd example of the Pennsylvania Railroad's T1 steam locomotive class and the only operational locomotive of its type, as well as the largest steam locomotive built in the United States since 1952. The estimated cost of PRR 5550 was originally $10 million, but an updated projected cost of $7 million was released with the acquisition of an existing long-haul tender from the Western New York Railway Historical Society in August 2017. Construction began in 2014 with the casting of the locomotive's keystone-shaped number plate. As of February 2024 the locomotive was 43% complete.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
