(1) Wheel-slip sensor cables.

(2)Frame-mounted bell..

(3) 4000-gallon fuel tank.

(4) Electrical cabinet air filter box.

(5) PTC control cabinet.

(6) Rerail frog.

(7) 81" nose.

(8) Ratchet-type hand brake.

(9) Nathan M-3 horn.

• The positive traction control (PTC) system uses these sensors to detect wheel slippage.  There are sensors on each axle; the rear truck has them on the opposite side.  Some units originally had all sensors installed on the fireman's side, but these were later changed for ease of maintenance.
• Bell is in the standard D&RGW location.
• Rio Grande's SD40T-2s had a slightly smaller fuel tank than usual-- 4,000 gallons instead of 4,400 gallons. As a result, they were about 2' 4-1/2" shorter, leaving a noticeable gap behind the front truck.
• These filters were for the air used to cool the electrical cabinet in the rear wall of the cab, and were standard on the Dash-2 series.
• PTC was installed on D&RGW tunnel motors beginning in 1985.  The box to house the control system circuitry was installed between the filter box and the blower housing behind the cab on the left side.
• Rerail frogs were standard D&RGW practice.  This is the later type.
• Rio Grande's earlier tunnel motors had the 81" nose.  The difference is noticeable when compared to the longer version, even though it is only 7 inches.
• This series of tunnel motor had the ratchet brake.  Others had a wheel-type brake.
• This unit still has the as-delivered Nathan horn.