This Atlas O Master 1649-1 is a powered 3-rail model of Union Pacific No. 900, an EMD F3A Phase 2 diesel locomotive. The model is equipped with Lionel-licensed TrainMaster Command Control and RailSounds and carries Union Pacific’s Armour Yellow and gray passenger scheme.
The original Atlas box photographed by TrainReference identifies the model as F3A Phase 2 (powered), Item #1649-1, Union Pacific #900 [3 Rail].
At a Glance
- Manufacturer: Atlas O
- Product line: Master
- Item number: 1649-1
- Prototype: EMD F3A Phase 2
- Railroad: Union Pacific
- Road number: 900
- Configuration: Powered A unit
- Scale: O
- Track system: 3-rail
- Command control: Lionel TrainMaster Command Control (TMCC)
- Sound: RailSounds
- Paint scheme: Armour Yellow and gray
Atlas O Master 1649-1
Atlas cataloged item 1649-1 as its powered 3-rail Union Pacific No. 900 F3A Phase 2. A companion version, item 1649-2, represented Union Pacific No. 902.
The TrainReference example retains its Atlas packaging, which provides unusually strong identification evidence. The box label specifically states the locomotive type, powered configuration, item number, road number and 3-rail system.
Model Features
Atlas documented the Master-series F3 with a substantial combination of mechanical, lighting, sound and command-control features:
- Highly detailed body with railroad-specific details
- All-metal grab irons
- Die-cast metal chassis, fuel tank and trucks
- Twin flywheel-equipped motors
- Directional golden-white LED lighting
- Accurate painting and lettering
- Operating diesel exhaust unit
- Electro-couplers
- Lionel TrainMaster Command Control
- RailSounds digital sound system
- Alternate full-scale pilot for the A unit
- Approximately 12.5 inches long
- Approximately 5 pounds
- O-36 minimum diameter curve for the A unit
The Atlas packaging also carries the Lionel RailSounds and TrainMaster Command Control marks, noting that these technologies were licensed by Lionel to Atlas.
The EMD F3
General Motors’ Electro-Motive Division introduced the F3 after World War II as part of the highly successful family of streamlined cab-unit diesels that helped accelerate the transition from steam to diesel power on North American railroads.
The F3 used EMD’s 16-cylinder 567-series diesel engine and was rated at approximately 1,500 horsepower per powered unit. A units contained a cab, while cabless B units could be coupled between or behind them to provide additional power.
F3 Phase 2
Railroad historians and model manufacturers commonly divide F3 production into several visual “phases” based on changes to body details during production. These phase descriptions are useful for identifying locomotives but were not separate EMD model designations.
Atlas identifies this model specifically as an F3A Phase 2, reproducing the configuration appropriate to Union Pacific No. 900.
Union Pacific No. 900
Atlas decorated this locomotive as Union Pacific No. 900 in the railroad’s familiar Armour Yellow and gray passenger colors.
Atlas offered a coordinated group of Union Pacific Phase 2 F3 models. In addition to powered A units 900 and 902, the range included matching B units and unpowered A units, allowing larger multiple-unit consists to be assembled.
TMCC and RailSounds
The 3-rail version documented here was designed for command-control operation using Lionel TrainMaster Command Control. Its RailSounds system provides locomotive sound effects, while the command system adds electronic control beyond conventional transformer operation.
This distinguishes item 1649-1 from Atlas’s corresponding 2-rail versions, which were cataloged separately with different electronics and product numbers.
Identifying This Model
The TrainReference example can be positively identified from the model and its original packaging:
- Atlas O Master
- F3A Phase 2
- Powered A unit
- Item #1649-1
- Union Pacific #900
- 3-rail
- Armour Yellow and gray paint
- TMCC and RailSounds
The box label photographed by TrainReference removes the ambiguity that can occur between the various powered, unpowered, A-unit, B-unit, 2-rail and 3-rail versions Atlas produced.
Original Photos
These original TrainReference photographs document Atlas O Master 1649-1 from multiple angles, including the body, running gear, roof, underside and original product label.
References and Further Reading
Related O Scale References
- C+LS Southern Pacific 4815 Train Master – O Scale
- Overland OMI-0195.1 Northern Pacific 1844 W-5
- Rivarossi 7201 Illinois Central 382 “Casey Jones” – O Gauge
Current Atlas Union Pacific F3 Listings
Current eBay listings related to Atlas Union Pacific F3 locomotives are shown below. For the exact model documented here, look for Atlas O Master, item 1649-1, Union Pacific No. 900, powered and 3-rail.
As an eBay Partner, I may be compensated if you make a purchase.

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