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Many of our locomotives are the last-of-their-kind and have interesting histories.

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Other K4 Pictures:

Larger picture of 3750 in Museum's Yard

Side view sketch of typical K4

Sketch of 3750 in action

3750's water scoop







The Museum's collection of priceless historic locomotives draws visitors from all over the world.

Many of these locomotives have special historic significance.

See, for instance:

Lindbergh Engine's story of a race against a plane.

GG1, sleek electric workhorse.


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Railroad Museum of Pennsylvania, a world class museum of railroad history in Strasburg, PA.
No. 3750 in Rolling Stock Hall. Click for larger view

PRR No. 3750 K4 Pacific

The Pennsylvania Railroad’s Class K4 Pacific (4-6-2) steam passenger locomotive No. 3750 is one of only two survivors of a great fleet that once numbered 425 engines. The other remaining K4, No. 1361 is owned by the Railroader’s Memorial Museum in Altoona, PA. Although somewhat overshadowed by its much-publicized sibling, the Railroad Museum’s K4 3750 has an interesting history that includes a bizarre identity switch that saved it from the scrap line after it had seen nearly four decades of service.

For many, the words “Pennsy K4” instantly evoke the distinctive visage of the engine in her prime: jutting headlight perched atop an enormous boiler; bright red, gold-numbered keystone centered on the smokebox door; massive paired cylinders; and a horizontally slatted “chicken-coop” pilot. In pre-diesel years, that familiar face was featured on many Grif Teller PRR publicity calendars that helped make the K4 a nationally known Pennsy trademark.

By W. R. Rowland

Bill Rowland on 3750.

"I've got this thing for Pennsy K4's. It goes way back to the mid 1930s when, as a kid, I watched those beauties daily scooting back and forth by the score on Pennsy's main line behind our backyard," he once wrote.

Bill Rowland was editor of Milepost, the Journal of the Friends of the Railroad Museum, for a number of years, and is responsible for its growth and high standards. He continues as Contributing Editor.

Bill was also one of the early members of the Friends, and played a major hands-on role in saving No. 3750 from years of neglect. His efforts in cleaning, scraping, painting, and restoring the locomotive rekindled his long-time love affair with this magnificent survivor of the Golden Age of Railroading, and he has written a number of articles about it and how it was saved.

This was written in 1989 for Milepost. For this presentation, minor changes have been made to the original text by staff, and by your Webmaster, who for a number of years was Bill's Associate Editor of Milepost. Bill's standards of "write it right the first time" have stood the test of time well.

The K4 not only looked good—it was good. In fact, it was one of the most successful steam locomotives ever built. In quantity, K4’s outnumbered any other steam passenger engine of any single class on any railroad in the United States. The product of Pennsy’s own designers, the K4 embodied many outstanding features of the line’s superb smaller Class E6 Atlantic (4-4-2) plus technology acquired from Pacifics such as the American Locomotive Company’s experimental K29 purchased in 1911. The Class L1 Mikado (2-8-2) freight engine of 1914 also contributed to the K4 design.

The first K4, No. 1737, that emerged from Pennsy’s Juniata Shops in 1914 underwent three years of exhaustive testing, after which it was virtually duplicated 424 times between 1917 and 1928. Of these, Pennsy built 350 in Altoona and contracted with Baldwin for the other 75. Aside from a few mechanical updates incorporated and backfitted during the twelve years of production, there were no significant alterations to the basic specifications, thus attesting to the soundness of the K4 design. Combining speed and power, the versatile locomotive easily adapted to service on all parts of the vast Pennsylvania Railroad system that included some of the country’s most demanding mountain terrain.

During more than thirty years of main line service, the K4, often double-headed where train weights and road grades required it, pulled all of Pennsy’s premier “Blue Ribbon” passenger consists, including the world-renowned Broadway Limited. In later years, the K4 was still hauling commuter consists and specials when Pennsy finally retired the class in late 1957. It had outlasted most other PRR steam passenger locomotives, including the mighty T1 Duplex (4-4-4-4) which had been designed to replace it in the 1940’s, and was still working long after diesels had replaced steam on most other major railroads. In the eyes of many experts, the Pennsylvania Railroad K4 Pacific ranks among the very best locomotives of all time.

Despite the superlatives, there was nothing spectacular or even unusual about the K4’s external configuration; it was a conventional, comparatively clean engine with few appurtenances to clutter up its smooth contours.

The “secret” of its success lay in the astute design relationships of weight and dimensions that combined to produce great tractive forces at high levels of power efficiency which enabled the K4 to operate effectively and economically wherever it was assigned. In keeping with the PRR’s image as a “conservative innovator” (i.e., use something new only when it’s been proven—preferably by somebody else), Pennsy designers simply refined state-of-the art locomotive technology to a level of performance that practically guaranteed success.

The K4, then, was a skillful blend of comprehensive test data from Pennsy’s own unique Altoona Test Plant, years of experience with an unparalleled fleet of swift passenger locomotives, and the “brainpickings” from other builders who also were developing large Pacifics.

The heart of the K4 was its long, large-diameter tapered boiler and huge “square-shouldered” Belpaire firebox, the latter a hallmark of Pennsy steam engines. The 27 x 28-in. cylinders contained the pistons that imparted tremendous power to six 80-in. drivers via a unique mechanism of lightweight, hollow-ground piston rods, crossheads, and nickel-chrome steel main and side rods, all regulated by Pennsy’s preferred Walschaerts valve gear.

A four-wheeled pilot truck and a two-wheeled, three-point-suspension trailing truck provided good stability for high-speed operation over difficult track. During the production years, the original hand-operated screw reverse was replaced by a power reverse that was backfitted to earlier engines.

Over the years, the K4 was coupled to a variety of tenders, the most widely used being the high, large-capacity Kiesel units originally designed in 1926 for the larger M1 engines. Surprisingly, most K4’s were not equipped with automatic stokers until Federal law mandated their use in the 1930’s. But once installed, stokers markedly increased the K4’s already impressive performance.

In common with many American railroads, the PRR went through a streamlining phase in the 1930’s, manifested largely by the Raymond Loewy-styled GG1 electric and “Fleet of Modernism” passenger cars. One K4, No. 3768, received a Loewy-designed torpedo-shaped full streamlined shroud in 1936; later, four more K4’s were given simpler shrouds that afforded easier access for maintenance, which was always an issue for streamlined engines. In time, all five locomotives reverted to their original unadorned configuration.

Beginning in 1947, most of the remaining K4 fleet was given the so-called front-end “modernization” treatment that still stirs debate among rail aficionados (some like it, most don’t). The distinctive projecting headlight, now smaller, was set further back atop the boiler flush with the smokebox face. The generator with its attendant piping, originally placed inconspicuously behind the old headlight, was mounted on a small platform above the smokebox door to make it more accessible. A wide work platform was added below the door, creating still more clutter on the formerly clean face. The box containing the cab signal apparatus that nestled under the smokebox behind the pilot beam was moved to the right running board just behind the cylinder steam pipe. Finally, the attractive slatted “chicken-coop” was replaced by a massive welded steel pilot with openings for steps on each side and a recessed drop coupler. The solid pilot, slightly curved to add just a hint of streamlining, supposedly improved collision protection. Both surviving K4’s are “modernized.”

Subsequent to production, Pennsy designers modified several K4’s as testbeds for new or improved equipment such as poppet valves, disc drivers, roller bearings, boosters, and “elephant ear” smoke lifters, none of which were backfitted to other engines. Aside from the fleet modifications already mentioned, the differences between the first K4 that rolled out in 1914 and the 425th engine that completed the roster in 1928 were minimal; in essence, one could say that all K4’s looked alike. This basic “sameness” of the entire K4 roster provides the gist of the strange story of the Railroad Museum’s K4 No. 3750.

Produced by the Juniata Shops in 1920, No. 3750 began its long but relatively undistinguished service career on Pennsy’s metropolitan corridor” tracks between New York and Washington, the nation’s busiest rail line. Her only claim to fame came in 1923 when she was assigned (for reasons unknown) to head the initial movement of the funeral consist that carried the body of deceased President Warren G. Harding to Ohio for burial. Harding’s sudden death shocked the nation. Despite allegations of corruption in his administration, he was an immensely popular president, and pictures of his solemn funeral special, with K4 3750 appropriately draped in elaborate mourning regalia, appeared on front pages across the land.

Following that sad event, No. 3750 resumed its role as just another engine among 425 others of its kind serving the Pennsylvania Railroad system. Records show that most of its service life until 1946 was east of Harrisburg, first on corridor tracks until they were electrified in the 1930’s, and then on lesser PRR Eastern Region divisions, primarily the Delmarva (Delaware, Maryland, Virginia peninsula), with a brief stint on the Middle Division out of Harrisburg.

In 1946, No. 3750 was leased to the Long Island Railroad for two years, and then returned to the PRR for its front-end “modernization” in 1948. For the next seven years, it worked in the Central Region west of Pittsburgh, mostly in Ohio. It came back east in 1955, assigned first to the New York area for several months and then to Philadelphia where it spent its remaining years in scheduled passenger service to Pemberton, New Jersey, and Atlantic City, and heading race track specials to Garden State Park.

In the mid-1950’s, No. 3750 was also used as a “loaner” to Pennsy’s New York & Long Branch line, temporarily replacing NY&LB K4’s sent to Camden for routine boiler flushing. During several of these assignments, noted rail photographer Don Wood captured it on film in his widely circulated photographs documenting the last days of Pennsy steam.

In October 1957, K4 3750 made its final revenue run. Retired at last after nearly 38 years of continuous service, it joined its few remaining siblings in the West Philadelphia engine house, just another worn-out old K4, silently awaiting the torch that would remove it from the roster forever. Then “fate” intervened.

Before continuing K4 3750’s unusual post-service saga, we must return to the original K4, No. 1737. That locomotive had been withdrawn from service in the mid-1950’s and set aside for preservation, a designee for the growing Pennsylvania Railroad Historic Collection of locomotives and rolling stock initiated in 1939. The “Pennsy Collection” evolved from an invitation extended to the nation’s railroads to provide historically and technically significant equipment to participate in the “live” pageant, “Railroads on Parade,” at the 1939/1940 New York World’s Fair.

Recognizing the historic importance of many of its active locomotives and cars, the PRR continued to set aside certain examples as “heirlooms” long after the Fair closed. Many of these pieces were moved to Pennsy’s Trenton, NJ Roundhouse and then to their Northumberland facilities near Sunbury; those that underwent refurbishment were stored inside the Northumberland roundhouse. The rest remained outdoors, exposed to the harsh elements, with little or no protective maintenance, as the Pennsylvania Railroad gradually slid into bankruptcy and ultimate dissolution.

Among the Northumberland locomotives was No. 1737, which the PRR rightfully concluded would be the ideal representative of its famous “carbon-copied” K4 class—the first of the best, so to speak. But Pennsy officials evidently didn’t realize that between the time 1737 was retired and left to stand idle in Altoona and the time it was singled out for preservation and moved to Northumberland for restoration, it had deteriorated so badly that only a complete rebuild could save it. Hard-pressed for funds and perhaps by then lacking the incentive that sparked their earlier preservation efforts, Pennsy sold the historic old locomotive for scrap. What happened next, in retrospect, seems almost ludicrous.

THE “RINGER”—K4 3750 wearing 1737’s number plate at Northumberland in 1960, ten years before move to museum site. Pennsy’s “switcheroo” saved her from the scrap line.
Click for larger view.
Apparently unwilling to admit the loss through neglect of one of its most historic and most famous locomotives, the PRR simply pulled another reasonably healthy K4 from the scrap line, stripped off its identification, and slapped on the 1737 number plate that had been saved for that purpose.   The “ringer,” of course, was none other than good old 3750, serving out its last days in New York and Long Branch commuter service.

It is difficult to believe that Pennsy actually thought they could pull off the switch unnoticed by railfans and railroad historians, the only people who really cared about such matters. Actually, there had been a precedent. Earlier, for the 1949 Chicago Railroad Fair, the PRR modified and renumbered Class E7 Atlantic No. 8063 (itself a rebuild from another class) to stand in for No. 7002 that set an unofficial but widely touted speed record of 127.1 mph back in 1905, and was subsequently scrapped in 1934 before the preservation movement took hold.

But the railroad community wasn’t fooled then nor was it fooled ten years later when Pennsy trotted out K4 3750 wearing 1737’s number. Whatever their reasoning, the important fact is that Pennsy saved another K4 when they granted 3750 her last-minute reprieve.

Why 3750 was chosen as 1737’s substitute instead of another recently retired K4 is another puzzle. Perhaps someone recalled its role in the Harding funeral. More likely, it probably stood at the end of its particular scrap line and thus was more accessible for a cheap move. In any event, it was transferred to Northumberland where it remained in storage for ten more years. In 1968, along with the rest of the collection, it was towed to Strasburg where it would be displayed as 1737 in the new Railroad Museum of Pennsylvania that opened its doors in 1975.

However, the move to Strasburg did not end K4 3750’s brush with destruction.  Although the entire Pennsy Collection had been acquired by the Commonwealth of Pennsylvania, years of litigation with the Penn Central (Pennsy’s successor) ensued before the terms of the acquisition were settled and the title to the collection cleared. In the meantime, 3750 remained exposed to the elements in the new Museum’s train yard, where lack of funds for adequate care added to its problems. By 1983, it looked almost as bad as its “alter ego” back in 1960 when the scrapper’s torch put a merciful end to the ruined 1737. But once again, it was rescued in the nick of time.

This time, help came from the newly organized Friends of the Railroad Museum. Starting in June of 1983, a small crew of FRM volunteers began the cosmetic refurbishment of the grand old engine, now numbered 1737. Almost a quarter-century’s accumulation of dirt, rust, and scale were carefully stripped from both locomotive and tender. Dents and cracks were filled and gaping holes in its boiler jacket patched. The cab was cleared of ankle-deep debris, and new wooden doors and window frames were fabricated. New seats were installed in the cab and missing fixtures replaced. The stoker, clogged with mud and debris, was cleared and drained.

Finally, after four months of preparation, the engine and tender were primed and painted in Pennsy’s traditional locomotive Brunswick green (near-black), and the tender relettered. Then, in a gesture to history and with a nod to the railfan community, the like-new locomotive was given back its original number, 3750.

On December 18, 1987, Pennsylvania Governor Robert P. Casey signed into law House Bill No. 1211 naming the PRR K4 as the “official” state locomotive, according that august title to both K4 survivors, 1361 and 3750.

Today, K4 3750 stands on proud display at the Railroad Museum of Pennsylvania, a great representative of Pennsy’s finest and a priceless artifact of the “Golden Age” of American railroading—a truly world-class locomotive twice rescued from almost-certain destruction and now preserved for posterity.

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