Spotter's Guide to the GTEL 8500 Horsepower "Big Blow" Turbine



Rivet Counter™ and Museum Quality™ “Big Blow” Turbine models both feature road number specific details. Throughout their careers, Turbine features evolved plus tenders were often swapped with other 3-unit sets. The following is a spotter’s guide to the many unique details that made the prototype legendary.

Note: The models featured in these images are hand-built decoration samples.  We use them as proof of concept models to test molding, painting, and assembly.  If you look closely, you will find imperfections.  These samples are used to make the production models as flawless as humanly possible.


“A” Control Unit

"Big Blow" Turbine "A" Unit - Early and Late Versions(

The first seven “Big Blow” Turbines were delivered without nose grab irons which were eventually added.  Road numbers 8 through 30 were delivered with nose grab irons.

All 30 were delivered with the Leslie S-5T-R air horn mounted on the cab roof.  Later in their careers, the horn was moved to the radiator section and a square base whip antenna was added.

Foreground: As delivered
Background: Modified


"Big Blow" Turbine "A" Unit As-Delivered Fuel Tank

As delivered, the fuel tank had two box shaped auxiliary reservoirs attached to the bottom. Fuel was supplied to the Cooper-Bessemer diesel engine which shuttled the 3-unit set at slow speeds. Note the rivet detail on the ends of the reservoirs.


"Big Blow" Turbine Modified Fuel Tank

Union Pacific eventually retrofitted the fuel tanks to increase capacity. This required additional plumbing for the fuel tanks as well as the air tanks.


"Big Blow" Turbine Trucks

Both "A" and "B" unit trucks include separate air reservoirs and anti wheel slip detectors.


"Big Blow" Turbine "A" Unit Radiators

As delivered, the radiators featured a large open grate. Note the detail underneath the etched metal grate on the model. The radiators were later modified with a shutter system that was likely used as a winterization hatch.

Foreground: As delivered

Background: Modified


Museum Quality "Big Blow" Turbine "A" Unit Opening Door

On the Museum Quality “A” unit, the cab doors open to reveal interior details such as the water cooler with straps and spigot. All Museum Quality "A" and "B" door handles (except the two between the "A" and "B") are separately applied too.


“B” Turbine Unit

"Big Blow" Turbine "B" Unit Air Intakes

We created three different “B” unit air intakes to match the prototype.

From front to back:
As delivered square
#30 intake tubes
Note: the tubes on #30 will be painted silver for production


"Big Blow" Turbine Dynamic Brake Versions

Both the “A” and “B” units include dynamic brakes. They are shaped like an H or I and are configured as H-H, H-I, or I-I depending on the road number.


"Big Blow" Turbine "B" Unit Doors

As delivered, “B” units featured see through ventilation louvers.


"Big Blow" Turbine Blanked "B" Unit Doors

 Later, UP blanked door and body panels. Note the rivet detail on the panels.


Museum Quality "Big Blow" Turbine "B" Unit Opening Doors

The Museum Quality “B” Unit doors slide open to reveal the turbine and generators inside.


Museum Quality "Big Blow" Turbine "B" Unit Blades Spin

The turbine fan blades are painted. The blade spins in the Museum Quality version.



"Big Blow" Turbine 23C and 24C Tenders

Tenders were often swapped between “Big Blow” Turbines. The shorter tender is a 23C and featured a 23,000 gallon capacity while the longer 24C tender carried 24,000 gallons of Bunker C fuel oil.


"Big Blow" Turbine Tender 6-Wheel Buckeye Truck

Buckeye 6-wheel truck.

Truck chains are included with the Museum Quality model. When attached to the truck, the model requires a minimum 22” radius curve.


"Big Blow" Turbine Tender 6-Wheel Commonwealth Truck

Commonwealth 6-wheel truck with separate brake cylinder and brake chain.


"Big Blow" Turbine Fuel Tender Detail

Under high magnification… note the step tread detail and rivets on the ladders.


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The Crew


Hear the Bessemer Cooper diesel engine in the "A" unit and the Turbine inside the "B" unit roar to life.  Also, see the powered "A" and "B" units with all-wheel drive and all-wheel electrical pick-up in action.

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  • Shane Wilson