MTH SD40T-2 Tunnel Motor Diesel Engine Susquehanna #3012 'O'
MTH SD40T-2 is a tunnel-motor diesel engine designed specifically for the Susquehanna Railroad to deal with their high-altitude tunnels and snow sheds, where hot locomotive exhaust would be drawn into the trailing units in multi-unit consists causing them to overheat. This design included oversized radiators and lower air intakes. The first SD45T-2 Tunnel Motors were delivered in February 1972, and were among the first “Dash-2” versions of EMD’s muscular 20-cylinder, 3600 hp freighter.
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
(2) Remote-Controlled Proto-Couplers
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
(2) Precision Flywheel-Equipped Motors
Operating ProtoSmoke Diesel Exhaust
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 Quillable Horn With Freight Yard Proto-Effects
Unit Measures: 18 5/8" 2 9/16" x 4"
Operates On O-42 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
Historical Info
If railroads had diseases, the Southern Pacific would have been diagnosed with asthma. The combination of high altitudes and numerous tunnels and snow sheds (tunnel-like sheds that protect track from snowfalls and avalanches) on its mountain divisions caused perennial breathing problems for SP locomotives and crews. In the steam era, this led to the development of cab-forward articulateds that allowed crew members to breathe tunnel air before the locomotive had polluted it. In the diesel era, the solution was the Tunnel Motor.
In a normal diesel locomotive, cooling air for the radiators is taken in near the top of the car body. In a long tunnel, however, hot engine exhaust and heated air from the radiators collects at the top of the tunnel. This hot air is taken into the radiators and cannot cool the engine sufficiently. In a multiple-unit diesel lashup, the result is that trailing units may overheat and automatically shut down. In a worst-case situation, the extra load will cause the overworked lead units to fail and leave the crew stranded in the tunnel. Electro-Motive’s answer for the Southern Pacific was a modification of its SD45, with the air intakes moved lower on the engine so they could take in cooler air. Extra-large radiators were placed on the roof of the engine, with the fans located below them to blow cooler air up from below.
The first SD45T-2 Tunnel Motors were delivered in February 1972, and were among the first “Dash-2” versions of EMD’s muscular 20-cylinder, 3600 hp freighter. Responding to complaints of crankshaft and bearing failures on earlier SD45s, EMD had beefed up its model 645 diesel motor. Perhaps more important, the Dash-2 series’ introduction of solid-state electronics ushered in the third generation of diesel technology. Transistors and circuit boards replaced the massive switches, contacts, interlocks, and relays of earlier diesels, making possible a range of innovations that would make life easier for diesel engineers in coming years.
