Both under the hood and under the frame, the GP40 exemplified EMD's product line in transition. Along with its less-powerful sister, the GP38, the Geep 40 was the first EMD locomotive with the model 645 diesel motor. Its predecessor, the 567 diesel that had powered EMD locos since the late 1930s - named for its 567 cubic inch displacement per cylinder - had become inadequate to meet customers' demands for higher horsepower.

Remarkably, the 645 was the same external size and weight as the motor it replaced, with the power increase achieved largely by increasing the cylinder bore. In its normally aspirated form, with a Roots blower pressurizing the incoming air, a 16-cylinder 645 cranked out 2000 horsepower; this was the motor in the GP38. The same engine with a turbocharger, however, put out 3000 hp in the GP40, with lower fuel consumption and emissions and improved high-altitude performance; the tradeoff was higher maintenance costs for turbo-equipped engines.

A design problem with turbochargers is "turbo lag": because the turbo's air compressor is powered by engine exhaust gas, the turbo doesn't become effective until the engine gets up to speed. In Alco diesels, this issue produced thick black smoke as the motors ramped up, earning them the nickname "honorary steam engines." In the 645 motor, EMD's engineers solved the problem with a gear train and over-running clutch, which drove the turbo at low engine speeds until the exhaust gas took over.

While the GP40 heralded the introduction of a new motor, it also marked the beginning of a long goodbye to the four-axle road diesel. Under the frame, railroads were seeing that six-wheel trucks, once an expedient for spreading out engine weight on lighter-duty track, were more suited to the increasing tonnage and speed of modern freight service. The GP40 and its successor, the GP40-2, were the last high-horsepower, four-axle Geeps to sell in large quantities. During a six-year production run that began in 1965, over 1200 GP40s were sold to U.S., Canadian and Mexican railroads. Notably absent from the list of original owners, however, were western heavy haulers Santa Fe and Union Pacific; both roads purchased fleets of six-axle EMD SD40s and SD40-2s. Although the lighter-duty, four-axle GP38 series continued to be a strong seller, the transition to the six axle, high-horsepower unit - which would become the standard road diesel of the 21st century - began in the era of the GP40.

 

 

Features:

 

Intricately Detailed, Durable ABS Body

Die-Cast Truck Sides, Pilots and Fuel Tank

Metal Chassis

Metal Handrails and Horn

Moveable Roof Fans

Metal Body Side Grilles

Detachable Snow Plow

(2) Handpainted Engineer Cab Figures

Authentic Paint Scheme

Metal Wheels, Axles and Gears

O Scale Kadee-Compatible Coupler Mounting Pads

Prototypical Rule 17 Lighting

Directionally Controlled Constant Voltage LED Headlights

Lighted LED Cab Interior Light

Illuminated LED Number Boards

Lighted LED Marker Lights

(2) Precision Flywheel-Equipped Motors

(2) Operating ProtoSmoke Diesel Exhaust Units

Onboard DCC/DCS Decoder

Locomotive Speed Control In Scale MPH Increments

Proto-Scale 3-2 3-Rail/2-Rail Conversion Capable

1:48 Scale Proportions

Proto-Sound 3.0 With The Digital Command System Featuring Freight Yard Proto-Effects

Unit Measures: 15 1/2" x 2 3/4" x 4"

Operates On 31" Radius Curves Diesel DCC Features

F0 Head/Tail light

F1 Bell

F2 Horn

F3 Start-up/Shut-down

F4 PFA

F5 Lights (except head/tail)

F6 Master Volume

F7 Front Coupler

F8 Rear Coupler

F9 Forward Signal

F10 Reverse Signal

F11 Grade Crossing

F12 Smoke On/Off

F13 Smoke Volume

F14 Idle Sequence 3

F15 Idle Sequence 2

F16 Idle Sequence 1

F17 Extended Start-up

F18 Extended Shut-down

F19 Rev Up

F20 Rev Down

F21 One Shot Doppler

F22 Coupler Slack

F23 Coupler Close

F24 Single Horn Blast

F25 Engine Sounds

F26 Brake Sounds

F27 Cab Chatter

F28 Feature Reset