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Alco "PA" Locomotives

Last revised:  August 18, 2023

By: Adam Burns

Alco's PA series has often been regarded as the most beautiful and aesthetically pleasing diesel ever built, even going so far as being designated an honorary steam locomotive!

There is no doubt that when one combs the library of diesel designs over the years the PA at the very least ranks as one of the best ever purely on its aesthetics.

The model was designed for passenger service and meant to compete with the Electro-Motive's highly successful E series that had debuted some years earlier.

Unfortunately, the PA never sold well for Alco as the original prime mover the builder employed was simply unreliable and problematic.  

Initial sales proved promising but after these issues cropped up most shied away from later variants.  Today, Doyle McCormack has successful restored former Santa Fe PA-1 #62-L into Nickel Plate Road #190. 

The locomotive he lovingly brought back to life has since been sold (March, 2023) to Genesee Valley Transportation of Pennsylvania, which plans to use the locomotive in excursion service. Additionally, the shell of another former Santa Fe PA is being restored in Texas.

Photos

2374283752368572683475309748.jpgA sharp Rio Grande PA-PB-PA set has train #18, the eastbound "California Zephyr," at Grand Junction, Colorado on September 13, 1956. Jackson Thode photo.

Overview

The original Alco PA (the P stood for Passenger and A referred to the unit having a cab) was built right after World War II in 1946 and was rated at 2,000 horsepower (later upgraded models were carried 2,250 horsepower).

The model was also cataloged with cabless streamlined units known as PBs (or just "Bs" as most referred to them), which matched the PAs and increased the horsepower rating.

When the PA was released Alco was already in catchup mode racing to release a competing model to EMD's revolutionary E series that had originally debuted before World War II in 1937 beginning with the EA (Baltimore & Ohio, E1 (Santa Fe), and E2 (Union Pacific).

Wartime restrictions prevented Alco from any significant work during the war but worked feverishly to catch up after the conflict had ended. This, unfortunately, hurt the builder immensely staying level with Electro-Motive.

Working in conjunction with General Electric on the model, the company used GE's Ray Patten to give the locomotive a fine exterior appearance (Patten also designed the PA's freight counterpart, the FA) and he unveiled an incredibly stunning carbody.  

However, Alco rushed the development of its new model 244 prime mover giving its engineers just a year after the war ended to work out any issues with engine.

Initially, the problems of the 244 were masked by Alco's then-excellent reputation as a locomotive builder.

The company had also used the 244, quite successfully, in the production of small switcher and road-switcher designs although the prime mover simply wasn't ready for heavy, main line applications. 

In June of 1946 the PA began testing on the Lehigh Valley clad in a beautiful demonstrator livery of maroon with silver trim with the combined GE/Alco livery adorned on the nose and carbody (the units were numbered 9077 and 9078).

The Santa Fe was immediately pleased with the new model and ordered twenty-eight PA-1s and sixteen PB-1s between September of 1946 and December  of1948. Other railroads soon followed and Alco would eventually sell 170 total PA-1s and PB-1s.

Rio Grande PA-1 #6003 and an F3A with the westbound "Yampa Valley" stopped at Winter Park, Colorado, circa 1965. American-Rails.com collection.

Reception

The PA-1 could produce 2,000 horsepower and provide 30,500 pound of continuous tractive effort using an A1A-A1A truck design (two outside powered axles with an unpowered center axle).

The locomotive was 65 feet, 8 inches long and its most stunning feature was its sweeping, streamlined nose and raked front windshields (the PA was nearly 10 feet longer than its FA counterpart).

As problems mounted with the PA-1 Alco rushed to correct the problem building an entirely new prime mover in the process, the model 251. This new engine proved much more reliable but was not available in time for the PA series.  


Data Sheets

PA-1
Alco Class606-DL-319
Entered Production9/19/1946
Years Produced9/1946-11/1949
Model SpecificationDL-304/A/B
Engine244, V-16
TurbochargerGeneral Electric RD1
Horsepower2,000
Carbody StylingGeneral Electric's Engineering Department
Length (Between Coupler Faces)65' 8"
Weight303,000 lbs. (Optional ballast to 319,000 lbs.)
Dynamic BrakesYes (Optional)
TrucksA1A-A1A
Truck TypeTrimount
Wheelbase15' 6"
Wheel Size42" (40" Optional)
Traction MotorsGE 746A2 (4): Upgraded to GE 752 (4) with DL304A variant.
Traction GeneratorGT566C1
Gear Ratio64:19 (80 MPH), 62:21 (92 MPH), 64:23 (100 MPH), 60:23 (104 MPH), 58:25 (117 MPH)
Tractive Effort Rating30,500 lbs. at 20 MPH with 62:21 gearing.
Top Speed117 MPH
PB-1
Alco Class606-DL-314
Entered Production9/19/1946
Years Produced9/1946-11/1949
Model SpecificationDL-305/A/B
Engine244, V-16
TurbochargerGeneral Electric RD1
Horsepower2,000
Carbody StylingGeneral Electric's Engineering Department
Length (Between Coupler Faces)63' 6"
Weight300,000 lbs. (Optional ballast to 314,000 lbs.)
Dynamic BrakesYes (Optional)
TrucksA1A-A1A
Truck TypeTrimount
Wheelbase15' 6"
Wheel Size42" (40" Optional)
Traction MotorsGE 746A2 (4): Upgraded to GE 752 (4) with DL304A variant.
Traction GeneratorGT566C1
Gear Ratio64:19 (80 MPH), 62:21 (92 MPH), 64:23 (100 MPH), 60:23 (104 MPH), 58:25 (117 MPH)
Tractive Effort Rating30,500 lbs. at 20 MPH with 62:21 gearing.
Top Speed117 MPH
PA-2
Alco Class606-DL-319
Entered Production3/31/1950
Years Produced3/1950-12/1953
Model SpecificationDL-304C/D
Engine244, V-16
TurbochargerGeneral Electric
Horsepower2,250
Carbody StylingGeneral Electric's Engineering Department
Length (Between Coupler Faces)65' 8"
Weight303,000 lbs. (Optional ballast to 319,000 lbs.)
Dynamic BrakesYes (Optional)
TrucksA1A-A1A
Truck TypeTrimount
Wheelbase15' 6"
Wheel Size42" (40" Optional)
Traction MotorsGE 752 (4)
Traction GeneratorGT566D1 (Upgraded to model GT586 in DL-304D variant.)
Gear Ratio64:19 (80 MPH), 62:21 (92 MPH), 64:23 (100 MPH), 60:23 (104 MPH), 58:25 (117 MPH)
Tractive Effort Rating37,000 lbs. at 19 MPH with 62:21 gearing.
Top Speed117 MPH
PB-2
Alco Class606-DL-319
Entered Production3/31/1950
Years Produced3/1950-12/1953
Model SpecificationDL-305C/D
Engine244, V-16
TurbochargerGeneral Electric
Horsepower2,250
Carbody StylingGeneral Electric's Engineering Department
Length (Between Coupler Faces)63' 6"
Weight300,000 lbs. (Optional ballast to 314,000 lbs.)
Dynamic BrakesYes (Optional)
TrucksA1A-A1A
Truck TypeTrimount
Wheelbase15' 6"
Wheel Size42" (40" Optional)
Traction MotorsGE 752 (4)
Traction GeneratorGT566D1 (Upgraded to model GT586 in DL-304D variant.)
Gear Ratio64:19 (80 MPH), 62:21 (92 MPH), 64:23 (100 MPH), 60:23 (104 MPH), 58:25 (117 MPH)
Tractive Effort Rating37,000 lbs. at 19 MPH with 62:21 gearing.
Top Speed117 MPH

There has been confusion over the years with the so-called "PA-3" variant.   It appears some railfans came up with this designation in reference to the PA-2/PB-2, DL-304D and DL-305D variants, that included upgraded engine components including:

  • Water-Cooled Turbocharger (In place of the air-cooled design used on early versions.)
  • New fuel injection system to reduce smoke emissions.
  • Improvements to the exhaust manifold to improve its service life.
  • Hardened crankshaft to reduce failures.
  • Upgrade to GE's model GT586 traction generator.

According to John Kirkland's book mentioned above, Alco never cataloged a PA-3 model, referring only to the PA-1/PB-1 and PA-2/PB-2, along with their variants.

Interestingly, Alco initially never even cataloged a PA-2/PB-2. Instead, these were simply referred to by their PA-1/PB-1 model designation; DL-304C/D and DL-305C/D.

It was only after production ended that Alco subcategorized these as PA-2's/PB-2's.  In addition, information came to light some 12 years after production had ended, in November, 1965, that Alco did indeed intend to produce a PA-3/PB-3 if the passenger market had warranted such.

These were to carry specifications DL-304E/DL-305E but, of course, never entered production.


After witnessing initial sales of 170 units with its first PA-1 design the later PA-2 models sold a combined total of 77 units by the time production had officially ended in December of 1953.

These numbers were a mere fraction when compared to EMD's E and F series, which together sold thousands by the time the models were no longer cataloged in the 1950s and early 1960s.

Santa Fe PA-1 #65-L at Redondo Junction (Los Angeles), circa 1965. American-Rails.com collection.

While Alco’s PA was unpopular with most railroads it gained instant celebrity status with the railfan community.  A big reason for the model’s popularity, besides its good looks was the fact that it went extinct. 

After the last PA ended its career with the Delaware & Hudson (whose PAs were originally owned by the Santa Fe) in 1978 and left for Mexico none remained on U.S. soil for nearly 25 years.

Nickel Plate 190

Then, two PAs made their way back in 2002; one was acquired by the Smithsonian for restoration and the other went to renowned locomotive restorationist Doyle McCormack.

McCormack spent nearly 20 years restoring what was originally Santa Fe #62-L into Nickel Plate Road's "Bluebird" passenger livery and given #190.  Its prime mover was started for the first time in October, 2013 although the locomotive still required a bit of work to begin operating under its own power.

The restoration of NKP #190 (originally AT&SF #62-L) is a near miracle; it took several years just to negotiate the locomotives’ return to the United States and by that point nothing was left but the carbody shell. 

Production Rosters

PA-1

Total Built = 169

Owner Original Road Number(s) Serial Number(s) Date Built
Alco (Freedom Train)* 1776 74696 8/1947
Alco (Demonstrator) 9077, 9078** 75791, 75792 12/1949
Santa Fe 51L, 51B 75000, 75002 9/1946
Santa Fe 52L, 52B 75003, 75005 12/1946
Santa Fe 53L, 53B-55L, 55B 75315-75320 4/1947 - 6/1947
Santa Fe 56L, 56B 74688, 75322 7/1947
Santa Fe 57L, 57B 75321, 74689 7/1947
Santa Fe 58L, 58B 74690, 74691 8/1947
Santa Fe 59L, 59B-62L, 62B 76535-76542 10/1948 - 12/1948
Santa Fe 70L-73L 76087-76090 2-3/48
Denver & Rio Grande Western 6001, 6003 74684, 74685 1/1947, 2/1947
Denver & Rio Grande Western 6011, 6013 74686, 74687 4/1947
Erie Railroad 850-854 76908-76912 4/1949
Erie Railroad 855-857 77103-77105 9/1949
Erie Railroad 858-859 77501-77502 9/1949
Erie Railroad 860-861 75793-75794 11/1949
Gulf, Mobile & Ohio 290-291 74682-74683 11/1946 - 12/1946
Lehigh Valley 601, 602 75458, 75459 3/1948
Lehigh Valley 603-606 75460-75463 4/1948
Lehigh Valley 607-612 75775-75780 4/1948
Lehigh Valley 613-614 75781-75782 5/1948
Missouri-Kansas-Texas (Katy) 151A, 151C 76917-76918 4/1949
Missouri-Kansas-Texas (Katy) 152A, 152C 76919-76920 5/1949
Missouri Pacific 8001-8008 77503-77510 10/1949
New York Central 4200-4201 75328-75329 1/1947
New York Central 4202 76086 1/1948
New York Central 4203 76307 12/1948
New York Central 4204-4207 76913-76916 4/1949
New York, Chicago & St. Louis (Nickel Plate Road) 180-186 75330-75336 12/1947
New York, Chicago & St. Louis (Nickel Plate Road) 187-190 75454-75457 3/1948
New York, New Haven & Hartford 0760-0769 76076-76085 8/1948 - 9/1948
New York, New Haven & Hartford 0770-0784 76312-76326 1/1949 - 3/1949
New York, New Haven & Hartford 0785-0786 76906-76907 3/1949
Pennsylvania 5750A-5754A 74697-74701 10/1947 - 11/1947
Pennsylvania 5755A-5759A 75323-75327 11/1947 - 12/1947
St. Louis-Southwestern Railway (Cotton Belt) 300-301 77511-77512 11/1949
Southern Pacific 6005A, 6005C 75783-75784 5/1948
Southern Pacific 6006A, 6006C 76072-76073 6/1948
Southern Pacific 6007A, 6007C 76074-76075 7/1948
Southern Pacific 6008A, 6008C-6010A, 6010C 77097-77102 8/49
Texas & New Orleans (Southern Pacific) 200A, 200B - 202A, 200B 77085-77090 6/1949
Texas & New Orleans (Southern Pacific) 203A, 203B 77091, 77092 7/1949
Texas & New Orleans (Southern Pacific) 204A, 204B - 205A, 205B 77093-77096 8/1949
Union Pacific 604-607 76308-76311 1/1949
Union Pacific 994A-997A 74692-74695 8/1947
Wabash 1020, 1020A 77081-77082 5/1949
Wabash 1021, 1021A 77083-77084 5/1949

*  Became Gulf, Mobile & Ohio #292.

** Demonstrated in Canadian National colors.  Later became Missouri-Kansas-Texas (Katy) PA-2s #59A and #59C.

PB-1

Total Built = 39

Owner Original Road Number(s) Serial Number(s) Date Built
Santa Fe 51A, 52A 75001, 75004 10/1946, 12/1946
Santa Fe 53A-56A 75337-75340 4/1947 - 6/1947
Santa Fe 57A, 58A 74704-74705 7/1947, 8/1947
Santa Fe 59A-62A 76543-76546 10/1948 - 12/1948
Santa Fe 70A-73A 76091-76094 2/1948 - 3/1948
Denver & Rio Grande Western 6002, 6012 74702-74703 2/1947, 4/1947
New York Central 4300, 4301 75605, 75606 1/1948
New York Central 4302, 4303 75610-75611 12/1948
Pennsylvania 5750B, 5752B 75343-75344 10/1947
Pennsylvania 5754B, 5756B 75345-75346 11/1947
Pennsylvania 5758B 75347 12/1947
Southern Pacific 6005B-6007B 75607-75609 5/1948 - 6/1948
Southern Pacific 6008B-6010B 75786-75788 8/1949
Union Pacific 604B-606B 75612-75614 1/1949
Union Pacific 607B 75785 1/1949
Union Pacific 998B, 999B 75341-75342 9/1947

PA-2

Total Built = 81

Owner Original Road Number(s) Serial Number(s) Date Built
Alco/Demonstrator ("More Power for America") 8375 (became New York Central #4212) 75790 3/1950
Erie Railroad 862, 863 78732-78733 4/51
Missouri-Kansas-Texas (Katy) 154A, 154C 78349-78350 11/1950
Missouri-Kansas-Texas (Katy) 155A, 155C-157A, 157C 78726-78731 3/1951 - 5/1951
Missouri Pacific 8009-8012 78135-78138 4/1950
Missouri Pacific 8013-8018 78734-78739 5/1951 - 6/1951
Missouri Pacific 8019-8022 79042-79045 5/1952 - 6/1952
Missouri Pacific 8023-8026 78208-78211 6/1952
Missouri Pacific 8027-8030 78957-78960 7/1952 - 8/1952
Missouri Pacific 8031-8036 80045-80050 8/1952 - 9/1952
New York Central 4208-4211 78204-78207 6/1950
New York Central 4213-4214 79040-79041 5/1952
Southern Railway 6900-6903 80846-80849 10/1953 - 11/1953
Southern Railway 6904-6905 81081-81082 12/1953
Southern Pacific 6019-6020 77999-78000 8/1950
Southern Pacific 6021-6022 78001-78002 9/1950
Southern Pacific 6023 78740 4/1952
Southern Pacific 6024-6027 79036-79039 4/1952 - 5/1952
Southern Pacific 6028-6033 80434-80439 5/1953 - 6/1953
Southern Pacific 6034 80443 9/1953
Southern Pacific 6035-6045 80835-80845 9/1953 - 10/1953

Export

Owner Original Road Number(s) Serial Number(s) Date Built
Paulista Railway (Brazil) 900-902 80440-80442 10/1953

PB-2

Owner Original Road Number(s) Serial Number(s) Date Built
Alco ("More Power for America") 8375B (became New York Central #4304) 75789 3/1950
Southern Pacific 5918-5919 78219-78220 8/1950 - 9/1950
Southern Pacific 5920-5921 78212-78213 4/1952
Southern Pacific 5922-5924 80607-80609 5/1953 - 6/1953

Total Built = 8

PA-4

Total Built = 4

Morrison-Knudsen Rebuilds

Owner Original Road Number(s) Serial Number(s) Date Built Heritage
Delaware & Hudson 16 76535 10/1948 Santa Fe 59L
Delaware & Hudson 17 76537 11/1948 Santa Fe 60L
Delaware & Hudson 18 76541 12/1948 Santa Fe 62L
Delaware & Hudson 19 75318 5/1947 Santa Fe 54B, later 66L

0091284126361y1h187598626100789.jpgA handsome Santa Fe PA-PB-PA set has arrived in Pasadena, California with train #17, the westbound "Super Chief," in 1948. Russ Cole photo. American-Rails.com collection.

Preservation

While #190 does not have all original PA equipment since much  of it no longer exists, many parts are of Alco origin.  The Smithsonian's Alco PA, former AT&SF #59-L, has since been donated to the Museum of the American Railroad in Texas.

The goal now of the museum is to fully, cosmetically restore the locomotive (currently only an empty shell as well) back into its original AT&SF "Warbonnet" livery as #59-L.  Later restoration efforts may also completely return the locomotive to operational status. 

Like a lot of folks, I have always had a soft spot for Alcos, especially their PA so it will be great to see #190 and #59-L roll out of the shop for the final time either fully or cosmetically restored.

It was announced on March 2, 2023 that Nickel Plate #190 had been sold to Genesee Valley Transportation for operation on the company's Delaware-Lackawanna Railroad based in Scranton, Pennsylvania.  Shop forces will inspect the PA and carry out whatever remaining work is needed to allow the locomotive to begin leading excursions along the former Delaware & Hudson line in Northeastern Pennsylvania.

In any event, more information about the PA series can be found above regarding which railroads purchased the model. Finally, while not listed there was also the Alco PA-4 model. This was simply a rebuild (by Morrison-Knudsen) of four former AT&SF PA-1s, all of which went to the Delaware & Hudson in the 1970s.

They were renumbered 16-18 and retrofitted with Alco's much more reliable model 251 prime mover. They paraded around the D&H system for years before being sold to a Mexican railway and are the two that returned to the States in the early 2000s.  

0109518273152541t24158026920789.jpgRio Grande PA-1 #6001 in Denver, Colorado; July 1, 1961. Ed Fulcomer photo. American-Rails.com collection.

Sources

  • Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.
  • Kirkland, John F. Diesel Builders, The:  Volume Two, American Locomotive Company And Montreal Locomotive Works. Glendale: Interurban Press, 1989.
  • Pinkepank, Jerry A. Diesel Spotter's Guide.  Milwaukee: Kalmbach Publishing Company, 1967.
  • Schafer, Mike. Vintage Diesel Locomotives. Osceola: MBI Publishing, 1998.

SteamLocomotive.com

Wes Barris's SteamLocomotive.com is simply the best web resource on the study of steam locomotives. 

It is difficult to truly articulate just how much material can be found at this website. 

It is quite staggering and a must visit!