Model Railroad News Product Reviews

Atlas Master Line Penn Central GE U33B in HO Scale

This husky U33B example from General Electric’s U-boat production shows off the stubby pug nose that became common in the 1960s. The model is available from Atlas in standard DC, as well as DCC-sound versions.

Atlas Master Line Penn Central GE U33B in HO Scale

HO ScaleReview by David Otte/photos by the author

Although at face value Penn Central (PC) comes across to many railfans as that somber black bankruptcy road, its eclectic mix of diesel-electrics actually offers a colorful history of the nation’s locomotive builders, as well as the motive power trends of the railroad industry in the late 1960s through the mid-1970s. Alco, Baldwin, General Motors’ Electro-Motive Division (EMD), Fairbanks-Morse, General Electric (GE), and Lima-Hamilton were all represented within Penn Central’s fleet of more than 4,000 locomotives.

In particular, the four-axle high-horsepower market was just starting to take shape when New York Central (NYC) and Pennsylvania (PRR) decided to make their monumental merger of 1968. General Electric, which had made a splash at the beginning of the decade with its 2,500-hp U25B model, now competed with EMD and Alco in the then-new second-generation diesel horsepower race. Climbing from 2,800 to 3,000 to 3,300 and on to 3,600 horsepower, GE’s Universal Series went neck-to-neck with the pack and eventually pushed Alco right off its track. And Penn Central was present to witness it.

The release of Atlas’ highly anticipated GE U33/36B model in HO scale offers model railroaders a chance to relive some of those glorious diesel days in miniature. For Penn Central, the U33B was the most powerful four-axle locomotive on its roster. Atlas has seen fit to replicate four different members of its fleet: 2916, 2921, 2937, and 2951, each available factory equipped with Digital Command Control (DCC) and sound (Gold Series) or as direct current (DC)/DCC-ready (Silver Series) models. A sample of the latter analog version will serve as our focus for this PC remembrance review, which, along with the participation of ESU LokSound, affords the opportunity to experience a sound decoder installation as well.

Penn Central 2915 sits with a roster mate from Erie Lackawanna in this March 21, 1977, view. Penn Central and Erie Lackawanna, along with other northeastern U.S. roads, saw incorporation in Conrail on April 1, 1976, by the U.S. government following PC’s failure. Note the non-standard typeface employed for the numerals on the cab. Kevin EuDaly collection

The History of GE’s Four-Axle U-Boat

Having collaborated in the past with other diesel locomotive builders such as Alco and EMD, GE management determined by the mid-1950s that it was time for the company to enter the road freight diesel locomotive market. At the outset of that endeavor, GE chose long-time business partner Cooper-Bessemer’s FDL-series engine around which it designed its new locomotive. Cooper-Bessemer had developed a turbo-charged, four-cycle 2,500-hp prime mover in 1958 — the now-famous FDL16 model. The U25B — the first high-horsepower locomotive on four axles — was born in the spring of the following year.

GE’s U25B would come to typify second-generation diesel locomotive designs. Two of the new mainline diesels could easily outperform three conventional cab units: Fs, FAs, or C-liners. The 252,000-pound locomotive, outfitted with four GE-752 traction motors and a GT598 main generator, could muster a 75,000-pound starting tractive effort at 30 percent adhesion and a 64,000 continuous tractive effort at 10.7 miles per hour. Its 40-inch diameter wheels were commonly geared at a ratio of 74:18, allowing a maximum speed of 70 miles per hour. Dynamic braking was offered as an option.

The U25B distinguished itself from other offerings of the early 1960s by its many technological breakthroughs bettering this GE release from other first-generation diesels. General Electric furnished its U25B with advanced wheel-slippage control, maximizing tractive effort. The pressurized engine and electrical compartments received air for combustion and cooling from a centralized filtered air system, which kept out harmful dirt and foreign matter. Air, fuel, and water piping ran under the walkway on one side of the locomotive and wiring was on the opposite side — a further attempt to keep maintenance time to a minimum.

Although the initial response to GE’s new design was slow (the first sale of U25Bs not coming until the summer of 1961), its shops were soon overwhelmed with orders. Some 16 railroads purchased these early “U-Boats” — nickname reported having been created by a Rock Island crew and a moniker that would stick for the entire Universal Series of locomotives to come. PC predecessor roads NYC, PRR, and New Haven invested in a total of 155 units. GE had constructed some 478 U25Bs by the end of production in early 1966 — a line drawn in the sand, if you will, on an aggressive GE’s part to dare the other builders to rise to the occasion.

And rise they did. EMD countered in mid-1961 with its interim 2,250-hp, four-axle GP30 (948 sold) followed two years later with its 2,500-hp GP35 (1334 sold). By early 1966, the builder’s new “40 Series” lineup included the 3,000-hp GP40 model (1221 sold). Meanwhile, Alco introduced its “Century Series” in 1963, featuring the 2,400-hp, four-axle C-424 (98 sold), which was bolstered by the up-rated 2,500-hp C-425 model (91 sold) the following year, and, in 1966, the 3,000-hp C-430 (16 sold).

Atlas U33B

From the mundane appearance of Penn Central’s U33B to a 1970’s era decorator’s dream come true in Auto-Train’s U36B, Atlas’ new HO-scale high-horsepower U-boats arrive in a rainbow of colors. Note the use of photo-etched grilles on each unit’s radiator exhaust housing, as well as the presence of the photo-etched screens covering the early phase PC U33B’s carbody air intakes in contrast to the late phase AT U36B’s corrugated coverings, highlighted by the model manufacturer in dark gray paint.

Through tweaks and equipment upgrades, the FDL16 prime mover maintained GE’s foot in the race with a 2,800-hp U28B arriving on the scene in January 1966. While early production units kept the appearance of the U25B, by May of that same year, company engineers redesigned the carbody, pushing the cab forward a bit and giving the U-boat its more recognized pug-nosed appearance — a characteristic of GE locomotives for years to come. It was also about this time when an improved 3,000-hp model debuted, the U30B, directly challenging both EMD’s GP40 and Alco’s C-430, as the big three diesel builders approached the finish line. Sales of the U28B, limited to only a year of production, proved disappointing with just 148 sold, but the U30B found more takers with 296 erected by the end of production in March 1975 — the last of the four-axle U-boat lineup to be built.

Meanwhile, GE was not complacent just to meet the efforts of EMD and Alco but set out to overcome them in the four-axle race by offering a 3,300-hp locomotive via the delivery of two up-rated U30Bs to New York Central in September 1967. These particular units were denoted visually from other U30Bs by the increased size of their radiators at the rear of the carbody, extending out over the walkways enough that railfans soon referred to them as “wings.” A U33B model was officially cataloged two months later, and the delivery of 135 more 3,300-hp locomotives followed through June 1970 with Penn Central alone taking delivery of 83 units.

Seaboard Coast Line U33B

Perhaps the most eye-catching of Atlas’ initial U33B/U36B offerings is this Seaboard Coast Line (SCL) 3,600-hp unit, number 1776. The prototype is credited as being the first locomotive painted in a patriotic theme celebrating the nation’s Bicentennial. Atlas has done an outstanding job at recreating this complicated paint scheme and even provides the various spotlights and brass bell utilized on the real SCL 1776 for modeler application. It took me about an hour to install these details, which includes locating, via prototype photos, the location of each fixture, drilling the holes with a pin vise and No. 78 drill bit, and gluing the parts in place.

Designed for high-speed merchandise and piggyback service, the U33B was soon joined by the most powerful four-axle diesel of the day: the 3,600-hp U36B. Production of this model continued through December 1974 with a total of 125 built. These two high-horsepower prototypes were visually indistinguishable from one another. Seaboard Coast Line (SCL) favored the latter model the most, purchasing 108 U36Bs and subsequently immortalizing this GE locomotive through its decoration of SCL 1776 as the very first specially painted red, white, and blue diesel locomotive commemorating the nation’s Bicentennial celebration.

Following EMD’s introduction of its new “Dash 2” lineup of four- and six-axle locomotives in 1972, GE redesigned its better-selling U-boats to compete with the improved reliability and operational efficiencies gained by its GM counterpart. The horsepower race had evidently come to an end for the time being, and the 3,000 horsepower locomotive had become the standard-bearer. GE cataloged its new range of offerings as the “Dash 7” series with the B30-7 taking over for the U30B and the B36-7 for the U36B. While sales of the new EMD units continued to dwarf those of GE’s Dash 7, the advancements realized with this series and the sales of its subsequent Dash 8 models eventually propelled GE to the Number One spot by the mid-1990s.

Atlas U33B as PC 2916

Just like the prototype, Atlas’s new HO-scale U33/36B borrows much from the company’s previously released U30B tooling. In fact, just as displayed by this latest U-boat rendering, all the real four-axle Universal Series locomotives dating back to the U25B measured 60-feet, 2-inches in overall length with truck centers 36-feet, 2-inches apart (save the oddball U18B “Baby-Boats,” which rode on shorter frames and were intended for branchline service). For the Atlas HO versions, this means the approximately 8-5/16-inch-long, 3,300/3,600-hp models utilize the same die-cast metal frame and injection-molded sill and cab as their 3,000-hp brethren.

Atlas Penn Central U33B

Penn Central 2916 was one of 83 U33Bs owned by the railroad during its relatively short existence. Additional service under Conrail would keep these high-horsepower U-boats in the railfan’s eye through the mid-1980s. Usually assigned to high-priority through freights, the 3,300-hp units could be seen working systemwide while wearing the PC “worm” herald. PC/CR 2916 would later go on to work for Guilford Rail Systems before succumbing to the scrapper’s torch in the early 1990s.

As such, the latter detail — in particular, the cab — as originally discussed in Tony Cook and Peter Arnold’s Rock Island U33B review in the November 2017 issue of Model Railroad News, has been a point of contention with modelers for quite some time whereby the height of the window and headlight placement, as well as the profile of its roof, are in question. The cab, unfortunately, remains the weak link in all the Atlas U-boat offerings to date, both four and six-axle prototypes alike. While it’s easy for the frustrated rivet-counter modelers among us to demand the manufacturer retool the cab to fix these perceived deficiencies, the cost involved in doing so could have very well prevented the U33B/U36B model from ever coming to fruition. As a big U-boat fan, I can look past this transgression, for the time being, to see a much-needed model produced in 1:87.

Moving past the cab, Atlas has done a fine job of recreating the balance of the carbody of these high-horsepower U-boats with the appropriate number of access doors and hatches, panel lines, and rooftop lift rings all crisply molded in one of three different shells, each of which depict either early or late phase production characteristics, as well as the late phase with the option for a light package mounted in the nose. These attributes are further enhanced with a plethora of separately applied details too, just as seen on the Atlas U30B rendering: wire hand grabs, scale-sized handrail with properly modeled stanchions, and end platform drop steps, as well as road-specific air horn and antenna styles. Further details include the addition of small or large electrical boxes on the walkways per the original owner; a two-piece fuel tank with air reservoir details; and handbrake wheel, sand hatches, and bell added as appropriate; snow plow, coupler lift bar. Multiple unit/trainline air hoses decorate the pilots, and windshield wipers and window glazing anoint the cab with painted crew figures seated inside.

Like the prototypes, the U33B/U36B models ride atop either Association of American Railroads (AAR) Type B trucks or those of EMD’s Blomberg design, harvested from traded-in units, depending on the road name. The HO-scale trucks feature add-on bearing caps, brake cylinders, and swing hangers, as appropriate for the design.

Consequently, it’s also worth reiterating the previous review’s listing of production phase characteristics for the U33B/U36B too. While Atlas keeps it simple by referring to the major carbody changes as “early” and “late” phase, these higher-horsepower U-boats were actually just an extension of the U30B carbody’s development, which continued on in production — even if only briefly — after the last U36B was built. For starters, the Phase II U30B carbody is the basis for the later units, which is distinguishable from Phase I U30Bs by having its entire rear hood section made the same width as the radiator — a design change that occurred on U30B production in January 1968.

Plenty of separately applied details await the HO-scale modeler contemplating one of these new Atlas U-boat renderings. Just check out the features displayed by MRN’s Penn Central example: add-on fine scale handrail; uncoupler bars and air hoses on the pilot; end platform drop steps; wire hand grabs; windshield wipers; cab window glazing; three-chime horn; radio antenna; and detailed AAR type B trucks. Note also the tread plate pattern molded in the walkways, as well as the detailed painting and graphics, which include the PC’s practice of painting the end handrail and edges of the step treads yellow and the “DANGER 600 VOLTS” warning signs visible on the battery box doors.

By the time the previously mentioned pre-production U33Bs arrived on the NYC in September 1967, though, the carbodies being utilized were already the Phase II style and exhibited flat screens over the air intakes and a small taper or faring ahead of the radiator itself. To be more specific, you can identify these early U33Bs as Phase IIa. Phase IIb Boats, on the other hand, would see the taper or faring disappear from the radiator, and Phase IIc units would have their air intake coverings become raised corrugations. One final production change impacting the U36B production, in particular, would be the later Phase IId alteration initiated in early 1971 whereby the rib or drip rail that had run along the side edge of those radiator wings from the get-go would be removed. Consequently, all U33Bs were built with this drip rail while the bulk of the U36Bs were not.

That brings us to MRN’s sample of PC 2916, the prototype of which was delivered within a batch of 20 units in November 1968. The HO-scale rendering correctly displays attributes of Phase IIb production with the flat air intake screens nicely rendered from photo-etched parts. Additionally, it is equipped with the correct Sinclair style antenna on the cab roof, has its three- chime horn mounted to the left side on the hood directly behind the cab, and properly rides atop AAR Type B trucks.

Wrapped in an excellent application of satin black paint and sharp white graphics per the railroad’s practice, it’s a picture-perfect, as-delivered PC unit, except for one detail: the radiator wings lack the aforementioned drip rails. It would appear Atlas has tooled up only one radiator housing design, which lends itself well to the U36Bs it is producing but leaves the U33Bs somewhat naked in the eyes of the rivet counters. Nonetheless, for those concerned by the omission, adding the appropriate ribs made from some Styrene strip stock shouldn’t be too difficult for even the novice model railroader.

It’s interesting to note, Penn Central amassed a fleet of 83 U33Bs, starting with NYC’s pre-production units (numbers 2858 and 2859). After the merger, 66 more 3,300-hp units (numbers 2890–2955) were delivered between September and December 1968. PC management returned to GE for more units in mid-1970 and accepted 15 U33Bs that had originally been ordered by the Rock Island, which joined the PC roster as numbers 2956–2970. All 83 units survived the road’s merger into Conrail in April 1976 and carried the same road numbers through to their retirements in the early-to-mid 1980s.

In this comparison shot of the HO-scale U33B alongside an Atlas late-phase U30B model, one can see how the larger radiator housing of the 3,300-hp unit became the key feature railfans could use to distinguish these two U-boats apart. This view also affords us a sampling of the wonderful photo-etched screen and grille coverings found on these Atlas GE models, as well as the numerous other separately applied detail parts.

Regarding Penn Central 2916, the U33B joined Conrail’s roster as 2916 and reportedly received its first coat of blue paint in June 1978. Not long after that, the unit was retired and sold to Boston & Maine (Guilford Rail Systems) in 1984, becoming that road’s number 190. Boston & Maine 190 served for another four years, however, before seeing final retirement in August 1988. It was subsequently sold for scrap in 1992.


DCC Conversion and Operation

Under the carbody, Atlas’ HO-scale U33B/U36B follows its previous U30B release with an identical drive mechanism, which includes a flywheel-equipped can motor and all-wheel drive/electrical pickup. After checking that the wheel gauge and the Accumate knuckle couplers conformed to National Model Railroad Association standards on MRN’s DC sample, I wasn’t surprised to witness a smooth and quiet-performing locomotive on the test track with the directionally controlled LED-illuminated headlights and number boards glowing brightly in a well-lit room. These characteristics are consistent with all my other Atlas U-Boat offerings to date. Drawbar pull is nothing to get excited about, but at 3.3 ounces, a single unit can handle about 36 pieces of rolling stock on a level pike with minimum 22-inch radius curves.

What I did miss with this U33B sample was the rumblings of a big 16-cylinder FDL prime mover and all the digital audio trimmings that go with it. Thanks to ESU LokSound, though, this uncomfortable silence I was experiencing during operation would soon come to an end! The hobby electronics firm was kind enough to provide us with the same sound decoder as was being factory installed in the Atlas Gold Series renderings along with a quality 8-Ohms speaker to boot. While the decoder is a plug-n-play type utilizing a 21-pin connector, its brown-colored audio output leads will need to be soldered onto the terminals of the speaker.

With the carbody shell removed, we begin our installation of the ESU LoKSound decoder and speaker. Note the “open space” on the lighting board just before the 21-pin connection on which the new decoder will rest, as well as the factory-equipped speaker sound chamber at the rear of the die-cast metal chassis. The dual flywheel-equipped can motor and drive shafts extending out to each truck’s gear tower are also visible.

The first task of installing a decoder is, of course, removing the shell. For the Atlas U-boat family, this is a relatively easy task. Simply remove the coupler boxes screwed to the frame, flex the hood and cab sides gently away from the frame to loosen the assembly up, then firmly grasp the shell, either front or rear, and pull up. Once the carbody unsnaps from the chassis, it can be maneuvered free. Inside, one will find a lighting board equipped with both a standard 21-pin and 8-pin decoder plug, the latter of which is fitted with the dummy plug allowing for analog DC operation. Furthermore, as the chassis is designed to be used for both Atlas’ Silver and Gold edition models, a speaker mount is already in place at the rear of the frame.

I first soldered the decoder’s wire leads to the speaker’s terminal and left the approximate six inches of wire length intact so that I would have enough slack with which to work the two components into position. Once accomplished, the 21-pin connection was cleared of the wiring from the front headlight and motor leads routed through it by the manufacturer and the decoder was lined up with the pins and pushed down into place. The speaker mount with sound chamber was then unscrewed from the frame, the speaker inserted face down, and the box reattached to the frame; the audio wiring slack was then coiled up, and a tie wrap used to keep it in place. The final and perhaps most important step is to remember to remove that dummy plug from the 8-pin connector, or all your efforts will be for naught!

Penn Central U33B

With ESU’s LokSound V4.0 decoder and speaker now installed, all that is left to do before reattaching the carbody is the removal of the dummy plug from the 8-pin connector. This is a very important step, less you forget as I did, with the end result being a loud electronic screech that sounded as soon as I powered up the locomotive on the test track! Also, make sure that when the carbody is placed back on the chassis, it is pressed firmly down so that its plastic retainer tabs snap into their respective slots on the metal frame.

With the model reassembled and on the test track, I was rewarded with the rich sounds of a four-cycle engine at startup after engaging F8. The motor operation was good before, but more so under the control of this decoder, cutting the minimum slow speed in half. There are a total of 24 function-enabled keys, the default setting of which pretty much follow standard U.S.-based DCC protocols with the F2 playable air horn particularly my favorite. All function buttons are fully mappable, however, with an array of NMRA-based Control Variables to adjust at the whim of the DCC aficionado, such as the ability to manipulate the volume of each individual sound effect, as well as a master volume control. These notable attributes are all standard fare for ESU’s family of LokSound V4.0 decoders, though, the full manual of which can be found via the company’s website at

A Winning Combination

While it is true that there is justification for some disappointment regarding the Atlas U33B/U36B offering’s reuse of the less-than-accurate GE cab and that only a single radiator housing style was developed with which to model multiple production phases, I do understand and respect the monetary issue involved in such an endeavor. Regardless, I am still pleased that a rendering of these high horsepower four-axle prototypes has finally been made available in HO scale. And with the aid of a LokSound decoder, these models easily transform into a focal point of one’s 1:87 motive power roster. It’s a winning combination indeed!

Atlas Master Line Silver HO scale
U33B diesel locomotive
Penn Central 2916
#10002318, MSRP: $169.95

Atlas Model Railroad Co., Inc.
378 Florence Avenue
Hillside, NJ 07205

ESU LokSound
EDCC V4.0 Sound Decoder
GE 16cyl FDL
#90476, MSRP: $109.95

Speaker with Sound Chamber
16 mm x 35 mm 8 Ohms
#50325, MSRP: $8.49

23 Howard Street
Montoursville, PA 17754

RMC November 1999For more information on the GE U33B, I recommend the article “The General Electric U33B” by Ken Goslett found in the November 1999 issue of Railroad Model Craftsman. A complete production roster and full-color photos are included as are dimensioned HO-scale line drawings of the 3,300-hp, four-axle U-boat by Eric Neubauer.


PC Post Vol. 18, No. 3A membership to the Penn Central Railroad Historical Society (PCRRHS) includes a three-times-a-year color magazine, PC Post, containing articles about Penn Central prototype and model subjects, photographs, and more. You’ll find a downloadable PCRRHS membership form on the group’s website. You can also join the PCRRHS on its website. Annual membership starts at $35.

February 2018This review appeared in the February 2018 issue of Model Railroad News.


This article was posted on: January 31, 2018