The General Motors switching and transfer locomotive models described in this manual are as follows:
The switching-locomotives are customarily single units rated at 800 or 1200 HP, depending on the model. These switchers may be equipped for multiple unit operation.
A transfer locomotive consists of an "A" and "B" unit permanently coupled together. Only one cab is included on such locomotives, and that is on the "A" unit.
100 Diesel Engines The main generator and auxiliaries of these locomotives are driven by a V -type, 2 cycle, Model 567B diesel engine. The cylinders have an 8-1/2" bore and a 10" stroke. The two banks of the engine are arranged with respect to each other at an angle of 45 deg. Figure 1-4 shows the cylinder arrangement of the 8 cylinder 800 HP and 12 cylinder 1200 HP engines.
The SW8 is equipped with an 4-567B engine while the TR6 is provided with the same engine in each of its two units. The. SW9 is powered by a 12-567B engine while the TR5 is supplied with two such engines.
The engine is started by temporarily using the main generator as a starting motor. Current from a storage battery "motors" the main generator to rotate the diesel engine.
The 8-567B engine is equipped with a single scavenging air blower while the 12-567B has two such blowers. Each blower is equipped with an air filter, the elements of which are 4" thick.
101 Main Generator The main generator Model D15C is directly coupled to the engine through a flexible coupling, and furnishes direct current at a nominal 600 volts to the traction motors. This generator is a constant KW generator which at full throttle delivers 560 KW to the traction motors on the SW8 or 848 KW to the traction motors on the SW9.
102 Traction Motors Four Model D27 traction motors are used in each unit, mounted one on each axle. Each motor is geared to the axle which it drives by a motor pinion gear meshing with an axle gear. The gear ratio between the two gears is expressed as a double number such as 62/15. In this case the axle gear has 62 teeth while the pinion gear has 15 teeth.
During acceleration two steps of traction motor electrical connections (called transition) are used (see Fig. 1-1):
Transition is the term applied to the changing of traction motor connections on a diesel-electric locomotive so that full power may be obtained from the main generator within the range of its current and voltage limits. To look at it another way, transition is a method of adjusting the traction motor BACK PRESSURE, bucking the input of power from the main generator so that the bilck pressure will not become too high at higher speeds nor too low at lower speeds. Forward transition, from series to series-parallel, as the locomotive speed increases is automatic. Backward transition, necessary as the speed decreases below a certain value (Art. 206), is done manually.
103 Auxiliary Equipment. The auxiliary equipment on these locomotives is driven by direct drive, V-bets or by separate electric motors.
A 10 KW auxiliary generator is driven direct through flexible couplings from the rear gear train of the engine. It produces direct current at approximately 74 volts to charge the storage batteries and supply the low voltage circuits for lighting, control, generator fleld excitation, fuel pump operation, etc.
The single engine radiator cooling fan and traction motor blowers (one per truck) are belt driven. At an engine speed of 800 RPM the traction motor blowers rotate at 1733 RPM. The radiator cooling fan rotates at 1250 RPM on the SW9 and 833 RPM on the SW8.
The locomotive is basically equipped with a Gardner-Denver 3-cylinder, two stage air compressor driven through a flexible coupling and an extension shaft from the front end of the engine.
Headlights, front and rear are of the sealed beam type, each equipped with a 30 volt, 200 watt sealed beam lamp and three point dimming device. The cab heater motor is provided with a variable 3-speed switch located in the engineer's instrument panel.
104 Trucks These locomotives are equipped with the rigid type 4 wheel truck having friction bearings.
Two levers and two brake valve handles control the entire operation of the locomotive. These are the throttle and reverse levers which are mounted in the control stand, and the independent and automatic brake valve handles, Fig. 1-2.
105 Throttle Lever This lever controls the speed of the engine and the train speed in normal operation. The SW8 and SW9 locomotives are basically equipped with the pneumatic-hydraulic governor control commonly termed the AIR THROTTLE. Speed of the engine is controlled by air pressure transmitted from the throttle control stand to the engine governor. The engine speed increases as the air pressure is increased, by opening the throttle, and is decreased as the pressure is reduced, by closing the throttle.
When the throttle is opened, a cam actuated throttle switch is closed thereby enabling the main generator to produce power (assuming the generator field switch is IN and the reverse lever is in the forward or reverse position).
The STOP position is obtained by depressing the button on the end of the throttle lever and pushing the lever one step beyond the idle position. When the throttle is in STOP, the contacts of the shut-down switch being closed, energize the shut-down solenoid in the governor; this stops the engine. In order to start the engine the throttle must be in the idle potition.
| 1. | Battery Charging Ammeter | 6. | Trans. Forestalling Switch |
| 2. | Control Air Pressure Gauge | 7. | Bell Valve |
| 3. | Road Service Switch | 8. | Automatic Brake Valve |
| 4. | Throttle Lever | 9. | Sanding Valve |
| 5. | Reverse Lever | 10. | Independent Brake Valve |
106 Reverse Lever The reverse lever must NOT be moved from the FORWARD to the REVERSE position or vice versa, at any time the locomotive is moving. In the forward or reverse this lever causes the reverser switch and power contactors to become energized even though the throttle may be in idle. Direction of the locomotive is controlled by movement of the lever to the forward or reverse position. The reverse lever cannot be moved unless the throttle is in idle. In neutral the power contactors will not close when the throttle is opened. With the throttle in idle, the reverse lever can be removed from the control stand when the lever is in the neutual position. The operating controls are locked by removal of the reverse lever from the control stand.
107 Mechanical Interlocks On the Controller The levert on the control stand are interlocked so that:
The instrument panel contains gauges and light indicators to guide the engineman in the proper operation of the locomotive, Fig. 1-3.
108 Air Gauges The air gauges show the main reservoir, equalizing reservoir, brake cylinder and brake pipe pressures.
109 Wheel Slip Indicator The flashing of this light indicates that a pair or more, of the locomotives wheels are slipping.
On the SW9 (1200 HP), and TR5 (2400 HP) locomottves the continuous burning of this light indicates an overloading of the main generator. When this happens the engineman must manually cause backward transition to be made.
110 Lubricating Oil Pressure Gauge This gauge indicates the pressure of the lubricating oil at the rear of the engine. With hot oil the reading should be 20 pounds or more at 800 RPM.
111 Engine Temperature Gauge This gauge shows the temperature of the engine cooling water leaving the engine. Automatically controlled shutters will normally keep the cooling water temperature between 150 and 180 degrees.
112 Fuel Oil Pressure Gauge The pressure of the fuel in the return line from the engine to the main fuel tank is shown by this gauge. The pressure should be approximately 5 pounds.
The electrical control cabinet contains the main battery, control and light switches as well as their respective fuses. These switches are clearly labeled as to their purpose and are closed during normal operation. The more frequently used control switches are mounted within reach of the engineman at his control station.
113 Transition Forestalling Switch The transition forestalliig switch is a push-pull switch mounted on the control stand above the reverse lever and to, the left of the throttle. The function of this switch is to forestall an undesired forward transition such as when kicking cars on a lead. If this switch is pushed in (IN-SERIES), forward transition will not take place, regardless of locomotive speed or main generator voltage; the motor connections will remain in series. If the switch is pulled out (OUT-AUTO), forward transition will take place when the main generator voltage reaches the pick-up value of the forward transition relay "FTR." The motor connections will then change to series-parallel.
When in full throttle, backward transition from series-parallel to series is made by either closing the throttle to idle and then opening it again, or by reducing the throttle 1" or more and pushing the switch in (IN-SERIES), completing backward transition. The transition forestalling switch is mechanically interlocked with the throttle so that it can not be moved with the throttle wide open; the throttle must be partially closed.
114 Road Service Switch The road service switch is a toggle switch located on the right side of the electrical cabinet. This switch has two positions ROAD and SWITCHING. The switch should be placed in the position corresponding to the type of service being performed.
In the ROAD position modified maximum field starting is provided, while full maximum field starting is obtained when the switch is in the SWITCHING position.
When operating with multiple unit locomotives the function of the road service switch is trainlined, provided that the road service switch in the non-operative cab is left in the SWITCHING position.
115 Control Push-Button Switch Box The engineman's control push-button switch box is located alongside and to the left of the controller. This box contains the control, generator field, fuel pump, engine start and the main cab heater, switches and fuses. The switches are clearly labeled for their respective uses.
116 Light Push-Button Switch Box The light push-button switch box is located on the right cab wall forward of the side window. It contains the headlight, gauge light and cab light switches and fuses.
117 Headlight Bright And Medium Switch The headlight switch above the light push-button switch box, controls the front and rear headlights. The desired dim headlight push-button must first be IN before the headlight switch is operative. The front and rear headlights may be on dim at the same time if both switches are IN at the light pash-button switch box. Only one headlight can be on medium or bright at a time.
118 Motor Cut-Out Switch A motor cut-out switch is mounted on the electrical control panel. This switch permits the isolation of one of the power trucks following a minor failure or emergency in case it is desired to move the locomotive under its own power (see Art. 207-3).
119 Isolation Switch (If Used) An isolation switch is used on transfer locomotives or those equipped for multiple unit operation. This switch is mounted in a metal box near the rear window sill behind the engineman's control station. The switch has two positions START and RUN. In the START position the power plant is isolated from the normal control circuits and the engine speed will remain at, or be reduced to, idle. The reverser and power contactors will not operate. and the engine will not respond to throttle control. The STOP push button on the isolation switch box is effective only when the isolation switch is in the START position, Fig. 7-2.
120 General The locomotive is equipped with the latest schedule 6BL (USA) or 6SL (Canadian) air brake equipment.
The equipment and operation of the 6BL or 6SL brake is practically the same as that of the 6ET brake, with the exception of a self-lapptng independent brake valve and a few other modifications.
As all enginemen are more or less familiar with the operation of the 6ET brake, no detailed operation of the 6BL or 6SL will be included.
Special instructions for special applications may be had from the air brake manufacturer upon request by the customer.
121 Sanding Valve This valve is located on the brake stand just to the left of the automatic brake valve. Moving the double acting sanding valve forward operates the four sand traps in the forward direction. Four sand traps in the reverse direction are similarly operated by moving the sanding valve handle to the rear.
122 Locomotive Bell A 12" locomotive signal bell placed on top 'of the hood just ahead of the first exhaust stack. It is operated by a valve located on the brake stand, just to the right of the automatic brake valve.
123 Horn Valve The horn is operated by an air valve which is controlled by a pull-cord within reach of the engineer. A shut-off cock is included in the air line to the horn and must be open for normal operation. This cock is located just underneath the cab floor in the right front corner and can be reached through the right side access door.
124 Windshield Wiper Valves A needle valve located at each of the wipers controls their speed, also turning them on or off. A master valve located under the engineer's instrument panel controls the main air supply to the wipers.
125 Fire Extinguishers Two (2) one-gallon CTC fire extinguishers are provided on the locomotive, one located in the cab and one in the power plant compartment. Operating instructions are given on the outside of the container and are quite simple. Everyone should feel obliged to familiarize himself with these instructions as prompt action in an emergency may prevent a tragedy.
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The two ends of the engine are designated FRONT and REAR as shown in Fig.
1-4 which will serve to identify the cylinder locations, and sides of the
engine, as they may be referred to in this manual. The governor, water pumps
and lubricating oil pumps are on the front end. The blowers, oil separator
andgenerator are mounted on the rear end. The engine is so placed that its
front end is towards the front end of the locomotive when the locomotive is
operating in its normal forward direction.
126 Air Box Drains Each engine has two air box drain tanks
incorporated in the engine oil pan near the generator end, one on each side.
These tanks have a valve in the drain line so that they may be drained when
the locomotive is standing still, and sludge and oil from the tank will not
be carried onto the running gear.
127 Governor, Governor Speed And Safety Control A Woodward type PG governor performs the function of controlling speed of the diesel engine as directed by position of the throttle at the control stand. The ordering of the throttle are transmitted to the governor by air pressure on the SW8 and SW9, or by electrical circuits on the TR5, TR6 and switchers arranged for multiple operation. Thus, a pneumatic-hydraulic governor is basically used on the SW8 and SW9, while an electro-hydraulic governor is used on other arrangements. The governor protects the engine in case of low oil pressure or high vacuum on the suction side of the lubricating oil pump. In the event of such lubricating oil trouble the governor will immediately stop the engine. This action will be indicated by a push-button, on the front of the governor housing, moving out an approximate 1 /2 ", visibly exposing a red band around the button shaft. In the normal position the red band is not visible, nor will it be seen if the engine is shut down by any other method. Transfer locomotives are'equtpped with an alarm bell and yellow signal light which will be turned on in case of a lubricating oil failure. When the engine is stopped by governor safety control, the push-button must be reset before the engine can be started. When the engine is started and run at idling speed, the governor will stop the engine again after approximately 40 seconds, if the condition causing the original shutdown still exists. This time delay is provided to allow a check to determine the difficulty. If an attempt is made to run the engine above idling speed during the delay period, the governor will tmmedtiltely stop the engine should the oil pressure be low or the oil pump suction high. | 
Engine Cylinder Arrangement |
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128 Layshaft Manual Control Lever The layshaft manual control lever is attached to the end of the infector control shaft at the left front corner of the engine. This lever may be used for manually shutting down the engine as well as facilitating the starting of a cold engine.
129 Engine Ovrspeed Trip If the engine speed exceeds approximately 910 RPM an engine overspeed device located in the front end of the engine will trip and bring the engine to a stop. Once this overspeed device is tripped it must be reset manually (by pulling the lever counter-clockwise until it latches) before the engine can again be started, Fig. 6-4.
130 Load Regulator The load regulator is located under the engine hood near the left front corner of the engine. Movement of the load regulator is controlled by engine lubricating oil directed by the load regulator pilot valve and a dump valve (ORS) in the engine governor. The function of the load regulator is to automatically vary the battery field strength in the maingenerator, thereby maintaining power output, corresponding to a definite rate of fuel consumption as determined by the position of the throttle.
The load regulator is in minimum field when the long end of the brush arm is in the 11 o'clock position. Maximum field is obtained with the brush arm in the 2 o'clock position.
131 Electrical Control Cabinet The electrical control cabinet, in the forward end of the cab, contains the high and-low voltage equipment (contactors, relays, fuses, instruments, etc.).
132 Control Air Pressure Regulator The control air for operating power contactors, reverser, and air throttle is supplied from the main reservoir and is reduced to 80 +/- 3 pounds by the control air pressure regulator. This regulator is located in the compartment beneath the cab floor. The control air pressure is indicated on a gauge mounted on the right side of the electrical control cabinet in the cab. Control air pressure is adjusted by turning the knob on top of the regulator.
133 Storage Battery A 32 cell, 64 volt, 284-amipere (8 hour rating) battery is located in the battery box behind the cab. The battery supplies the power start the engine while also providing current to the low voltage system when necessary.
