Alaska Railroad's Unique, Streamlined RF-1s

Published: August 17, 2026

Alaska Railroad’s unique RF-1 “streamlined” Alcos (rebuilt from RSD-1s), including the two examples pictured below in 1971, were among the most distinctive diesels ever operated in North America. They were not factory streamliners but heavily rebuilt wartime military surplus units given full carbody shrouds primarily for passenger service on the railroad’s new Aurora trains, with important practical benefits for Alaska’s extreme winters.

Perhaps one of the most unique examples of streamlining ever attempted was that done by the Alaska Railroad when several RSD-1s were rebuilt between 1947-1949 and shrouded, and reclassified as RF-1As/RF-1Bs. Due to a power shortage two of the four remaining RF-1As were reactivated in August, 1971 and pictured here (1072 and 1078) in Anchorage on October 11th that year. Phillip C. Faudi photo.

Background: Surplus RSD-1s Arrive in Alaska

The Alaska Railroad’s first diesels were a pair of new Alco RS-1s (Nos. 1000–1001) delivered in 1944 specifically for the Whittier tunnel run. After World War II the railroad acquired a large fleet of surplus U.S. Army RSD-1s. These were six-axle (C-C) versions of the RS-1 design, built with lower-profile cabs for overseas clearances (many for the Trans-Iranian Railway supply route to the Soviet Union). They retained the 1,000 hp Alco 539 prime mover and were essentially RS-1s on six-wheel trucks.

The open-hood road-switcher design proved problematic in Alaska. Extreme cold made routine maintenance difficult, and the railroad wanted modern-looking power for upgraded passenger service.

The Rebuild Program and Purpose of the Shrouds

In 1947 the Alaska Railroad began converting RSD-1s into enclosed “carbody” locomotives for the new AuRoRa (later Aurora) streamliner service between Anchorage and Fairbanks. The inaugural train debuted that October for Alaska Day celebrations, with experimental units 1050A and 1051B. These early conversions were described as “extremely homely.”

Lessons from the prototypes led to better-looking units. In 1949–1950, Puget Sound Bridge and Dry Dock Co. of Seattle rebuilt additional RSD-1s into the RF-1 class. The work enclosed the machinery in a full streamlined carbody (side sheeting applied outside the original walkways), improved the overall lines, and converted the trucks from C-C to B-B. Some B-units (boosters) were also produced, with construction split between Seattle and the Anchorage shops (records for some were lost in a 1951 shop fire).

Primary purpose: Streamlined appearance and performance for passenger trains. These became Alaska’s first true streamliners and powered the Aurora.

Practical winter benefits: The enclosed carbody protected the engine and auxiliaries from severe cold, snow, and ice far better than an open hood. It also improved access and reliability for maintenance crews working in sub-zero conditions—exactly the issue the railroad faced with the original open-hood RSD-1s/RS-1s. Contemporary accounts and later modeling/historical notes from Alaska railroaders emphasize both the passenger aesthetics and the cold-weather practicality.

The RF-1As (cab units) received even numbers (non-sequential): 1052, 1054, 1070, 1072, 1074, 1076, 1078 (and the earlier experimental pair). RF-1Bs (cabless boosters) received odd numbers: 1053, 1055, 1057, 1065, 1067, 1069, 1075, 1077.

No. 1073 Pictured Above

Built February 1943 by Alco as U.S. Army RSD-1 No. 8052 (builder’s number 70673).

Acquired by the Alaska Railroad and initially rostered in the 1000-series (as 1023 in some accounts).
Rebuilt in 1950 (shroud applied 1949–1950 timeframe) as RF-1A 1072 with B-B trucks.
Served in passenger service (photographed on Train 36 at Healy in 1952 and at Curry Hotel in 1950) and later in mixed/freight and snow-plow helper roles.
Reactivated in August 1971 (along with a few other remaining cab units) during a power shortage.
Retired and scrapped in 1973.

Sister units such as 1070 (last to retire still in the original blue-and-yellow scheme, April 1970) and 1078 followed similar paths. A few survived into the early 1970s in black-and-yellow paint, used as rotary snowplow power until summer 1972.

Specifications (RF-1 Class, Approximate)

These are derived from the RSD-1 base with documented rebuild changes:

Specification	Detail
Builder (original)	American Locomotive Company (Alco)
Original Model	RSD-1 (U.S. Army surplus)
Rebuilt Class	RF-1A (cab unit) / RF-1B (booster)
Horsepower	1,000 hp
Prime Mover	Alco 539 (6-cylinder)
Original Trucks	C-C (six-axle)
Rebuilt Trucks	B-B (four-axle)
Gear Ratio	75:16 (double reduction, retained)
Service Weight (rebuilt)	Approximately 253,700 lbs
Starting Tractive Effort	~63,500 lbs (RSD-1 base; adjusted after B-B conversion)
Maximum Speed	Approximately 65 mph
Rebuild Location	Primarily Puget Sound Bridge & Dry Dock Co. (Seattle); some B-units in Anchorage shops
Rebuild Period	1947 (experimental) / 1949–1953 (production)

Exact weights and dimensions varied slightly by unit; the enclosed body added visual bulk while the truck conversion and other changes kept weight close to the original.

Rosters

RF-1A Cab Units

Road No.	Builder No.	Built	Original Identity	ARR Acquisition / Rebuild	Retirement	Notes
1050	70661	1943	US Army 8040	1947 (as 1050A)	1963	First streamliner; scrapped 1963
1051	70675	1943	US Army 8054	1947 (as 1050B)	1964	Scrapped 1965–67
1052	70676	1943	US Army 8055 (ex ARR 1020)	1949	1956	Scrapped 1966–68
1054	70677	1943	US Army 8056 (ex ARR 1087)	1950	1964	Scrapped 1965–67
1070	70668	1943	US Army 8047 (ex ARR 1022)	1949–50	1973	Last in original blue/yellow; scrapped late 1973
1072	70673	1943	US Army 8052 (ex ARR 1023)	1950	1973	Reactivated 1971 for power shortage; scrapped 1973
1074	70657	1943	US Army 8036 (ex ARR 1024)	1950	~1966	Scrapped 1966–67
1076	70667	1943	US Army 8046 (ex ARR 1025)	1950	1973	Scrapped 1973
1078	70674	1943	US Army 8053 (ex ARR 1019)	1949	1972	Used on rotary snowplow service; scrapped 1973

RF-1B Booster Units

Road No.	Builder No.	Built	Original Identity	ARR Acquisition / Rebuild	Retirement	Notes
1053	70642	1942	US Army 8021 (ex ARR 1089)	1950	1965	Scrapped 1966–68
1055	70659	1943	US Army 8038 (ex ARR 1002)	1950	1965	Scrapped 1966–68
1057	69993	1942	US Army 8001 / nee NYSW 233	1950	1965	Scrapped 1965–67
1065	70656	1943	US Army 8035 (ex ARR 1015)	1952 (after fire damage)	1972	Scrapped 1973
1067	70647	1942	US Army 8026 (ex ARR 1016)	1953	1965	Scrapped ~1966
1069	69567	1941	US Army 8002 / nee MILW 1678	1950	1963	Scrapped ~1963
1075	70672	1943	US Army 8051 (ex ARR 1011)	1950	~1964–65	Scrapped mid-1960s
1077	70664	1943	US Army 8043 (ex ARR 1012)	1950	~1965–66	Scrapped mid-1960s

Notes on the roster: Numbers were non-sequential. Early experimental pair (1050A/1050B) were rebuilt in Alaska; most later A-units were converted by Puget Sound Bridge & Dry Dock in Seattle (1949–50). Some B-units were completed in Anchorage (records partially lost in the 1951 shop fire). All were eventually scrapped; none survive.

Service Life, Paint, and Fate

Early units wore the attractive blue-and-yellow passenger scheme associated with the Aurora. Later survivors received black-and-yellow. They handled passenger, mixed, and eventually secondary freight/snow-fighting duties as newer EMD F-units and Geeps arrived in the 1950s–60s.

By the early 1970s the RF-1 fleet was obsolete. Most were retired and scrapped between the mid-1960s and 1973. None survive today.

These locomotives remain a fascinating footnote in diesel history: wartime military surplus transformed in Seattle and Anchorage into Alaska’s first streamliners, blending passenger-era styling with hard-earned adaptations for one of the most demanding operating environments in North America.

An Alaska Railroad publicity photo featuring the new "Aurora" in 1947. The RF-1A and RF-1B testbed set pictured here, 1050A and 1051B, retained their C-C trucks.

History of the Aurora Passenger Train

The Aurora (originally stylized AuRoRa) was the Alaska Railroad’s first true streamliner and marked a major postwar upgrade in passenger service.

Origins and Debut (1947) After World War II the railroad sought to modernize its image and improve the Anchorage–Fairbanks passenger run. In 1947 it rebuilt the first two surplus RSD-1s into full-carbody units (1050A and 1050B). These became the power for the new train.

October 16, 1947: No. 1050 made a shakedown run from Anchorage to Palmer and back with a trainload of schoolchildren.
October 18, 1947: Formal ceremonies were held at the Anchorage depot. A military band played, steam locomotive No. 6 (temporarily renumbered 1 for aesthetics) was displayed as a contrast between old and new, and the streamliner was christened AuRoRa. It then departed north for the first Alaska Day celebration at the Mount McKinley Park Hotel.

The train was painted in the attractive blue-and-gold scheme that became iconic for Alaska Railroad passenger power. It offered significantly improved service on the long Anchorage–Fairbanks route (roughly 350–360 miles), reducing travel time as track conditions improved.

Service Evolution The Aurora operated as a daytime streamliner. In summer 1956 the railroad added the Midnight Sun, which featured overnight sleeper-car service; that service ended in the mid-1960s. By the early 1950s competition from highways had already forced the end of through passenger service to Seward (1953).

As newer EMD F-units arrived in the early 1950s, the RF-1s gradually shifted from primary Aurora power to secondary and mixed-train duties, though they remained associated with the train’s early years.

Modern Legacy The Aurora name survives today as the Aurora Winter Train. It operates between Anchorage and Fairbanks on weekends (northbound Saturdays, southbound Sundays) from mid-September through mid-May, with occasional mid-week trips. Like the historic Hurricane Turn, it offers flag-stop service at many intermediate points, making it one of the last true flag-stop trains in the United States. The modern version is a continuation of the same corridor service that began with the 1947 streamliner.

The original AuRoRa remains one of the most significant milestones in Alaska Railroad passenger history—the moment the railroad stepped into the streamlined diesel era with purpose-built (or rather purpose-rebuilt) power tailored to both passenger appeal and the harsh Alaskan operating environment.