A schematic flow diagram of the engine cooling system is shown in Fig. 4-1. Water is circulated through the cooling system by two centrifugal type pumps mounted C. on the front end of the engine. Water, drawn from the engine cooling water tank and oil cooler by the pumps, is forced through the engine and then through the radiator where it is cooled. After leaving the radiator, the water flows through the oil cooler and then to the suction side of the pumps where the cycle is repeated.
The radiator is made up of two banks; each bank consists of five radiator sections. Water leaving the engine and entering the radiator is divided between the right and left bank radiator sections. In each bank, two radiator sections are located at the cab end of the long hood, and three radiator sections are located at the opposite end of the long hood. The front and rear radiator sections of each bank are connected together by a water manifold.
Flow of cooling air through the finned radiator sections is controlled by shutters and four AC driven cooling fans. The operation of the fans and shutters automatic. When the fans are operating, air flows up through the radiator sections and is discharged from the roof of the carbody.
The four AC driven cooling fans are mounted in the roof of the long hood above the radiator sections. Two fans control the cooling air through the cab end radiator sections of each bank and two fans mounted at the other end of the long hood control the cooling air through the rear banks of radiator sections. The fans are numbered one to four, beginning with the #1 fan located nearest to the cab end of the long hood.
Fig. 4-1 -- Schematic Of Cooling And Lube Oil Systems
Shutters are located on each side of the long hood just below the front and rear radiator banks. The shutters controlling the air flow through the #1 and #2 cooling fans are opened automatically by electropneumatic control when the #2 cooling fan is started. The shutters controlling the air flow through the #3 and #4 cooling fans are opened automatically when the #4 cooling fan is started.
The operation of the cooling fans is controlled by temperature control switches, Fig. 4-2. The temperature control switches, set to close and open at various engine water temperatures, control the operation of the AC contactors. Closing of the AC contactor, starts the respective cooling fan. The temperature control switches are set to close the AC contactors as follows (the temperature control switch will open approximately 10 degs F. below this setting):
400 Operating Water Level Operating water levels are stenciled on the water tank next to the water level sight glass to indicate minimum and maximum water levels with engine running or stopped. The engine should never be operated with water below the low water level, Fig. 4-3. Progressive lowering of water in gauge glass indicates a water leak in the cooling system.
401 Filling Cooling System The system is filled either through the filler pipe located on the roof of the locomotive above the water tank, or through the filler pipe on either side of the locomotive.
To fill the system proceed as follows (Steps 1 to 5 are necessary only when engine is dry or nearly dry):
If the cooling system of a hot engine has been drained, do not refill immediately with cold water. If this is done, the sudden change in temperature might crack or warp the cylinder liners and heads.
CAUTION:
1. Do not attempt to fill the cooling system through the drain pipe located underneath the locomotive.
2. The system should not be filled above the maximum water level indicated on the water tank to prevent:
402 Draining Cooling System The entire cooling system can be drained through the drain valve on the floor in front of the engine, with the exception of the water trapped in the water pump on the right hand side of the engine. To drain the right hand water pump, open the drain on the bottom of the water pump housing.
403 Cab Heating and Ventilating Cab heaters are complete with defroster and fresh air ventilators, Fig. 4-4. Fresh air is taken in through a louver in the cab wall and is controlled by a fresh air damper within the heater.
Controlled by a rheostat type switch, a 1/6th HP variable speed fan motor draws in fresh air or recirculates cab air. The fan forces air through a hot water radiator and exhausts the heated air out onto the cab floor.
The defroster is a simple non-adjustable baffle and duct arrangement where the volume, temperature, and velocity of the discharged air is dependent upon the setting of the fresh air damper, outlet damper, and speed of the motor.
Fresh air is controlled by the knob nearest the cab wall while the fan motor OFF-ON and speed control knob is farthest from the cab wall. A small knob located on the outlet damper controls the amount of air entering the cab through this outlet.
 Cab Heater, Defroster And Fresh Air Ventilator -- Fig. 4-4 | Cab heater water is taken from the water pump discharge located at the
front, or governor, end of the engine. The water proceeds, through a
shutoff valve, the length of the engine and progresses through one cab
heater and then the other (in series) and discharges into the engine
system at the radiator header. Water drains from the cab heater system at
two places. One drain valve is located at the right front corner of the
engine beneath the floor level. The other cab heater drain is at the left
rear corner of the cab below the floor.
Steam tracer lines are lagged to the heater water supply and return lines throughout their run in the locomotive. The tracer line exhausts into the cab heater piping under the cab floor. Steam is supplied to the tracer lines from the engine side of the engine steam admission valve. |
|---|
404 Engine Room Winterization On special order GP9 locomotives can be equipped with a winterization duct and carbody filter covers which results in higher engineroom operating temperatures. The winterization duct consists of a housing and a damper arrangement over the #3 cooling fan which allows, under certain conditions, the warm air discharged from the #3 fan to enter the engineroom. In the summer position, the duct leading to the engineroom is closed off, Fig. 4-5, and all the air from the #3 fan is exhausted to atmosphere. In the winter position the duct is opened so that, depending on the carbody filter blocking, warm air will enter the engineroom. A handle on he outside of the duct, secured in position by a bolt, controls the operation of the damper in the air duct.
The covers for the carbody filters are held in place on the filter by two spring clips. The covers are placed on filters at location "X" on both sides of locomotive as indicated in Fig. 4-6. Once the covers are applied they can be left in place throughout the winter season and removed in the spring.
When operating in extremely cold weather or under heavy snow or blizzard conditions, all of the filters (six) should be "closed." When operating in mild winter weather all of the carbody filters should be opened.
When operating in temperature above 75 degs F. ambient all carbody filters must be unblocked and the "Winterization" air duct "closed."
A schematic diagram of the lubricating oil system is shown in Fig. 4-1. Oil under pressure is forced through the engine for lubrication and piston cooling by the positive displacement combination piston cooling and lubricating oil pump. After circulating through the engine, the lubricating oil drains into the oil pan sump. The positive displacement scavenging oil pump draws oil from the sump and forces it through the filter and W oil cooler. From the oil cooler, the oil is delivered to the oil strainer assembly where it is ready for recirculation by the combination piston cooling and lubricating oil pump. Since the scavenging oil pump delivers a greater quantity of oil to the strainer than is required by the lubricating oil and piston cooling pump, the excess oil returns to the oil pan sump.
A relief valve is built into the filter in order to allow the passage of oil to the strainer in excess of the capacity of the oil filter elements.
A relief valve is also mounted on the left side of the accessory end of the engine. This valve is located in the discharge side of the lubricating oil pump. The purpose of this valve is to limit the maximum pressure of the lube oil entering the engine lube oil system to approximately 50 pounds.
405 Oil Level The oil level should be checked, Fig. 4-7, with the engine hot and running at idle speed. The dipstick should show a level between "Low" and "Full," Fig. 4-8. The "dipstick" is located on the right side of the engine. When the engine is stopped,the oil in thefilter and cooler will drain back into the oil pan. If the oil level is checked with the engine stopped, the reading on the "dipstick" will be above the "Full" mark.
 Oil Dipstick -- Fig. 4-8 | |
|---|---|
 Lube Oil Level -- Fig. 4-7 |  Adding Oil To Engine -- Fig. 4-9 |
406 Adding Oil to System Oil may be added with the engine running or stopped. When oil is added to the system, it MUST be poured through the opening having the square cover, Fig. 4-9, on top of the housing. Should the round caps be removed while the engine is running, hot oil under pressure will come from the openings and possibly cause personal injury.
407 Oil Pressure Adequate lubricating oil pressure must be maintained at all times when the engine is running. Upon starting and idling an engine it will be noted that the oil pressure builds up almost immediately. In the event of cold oil the pressure may rise to the relief valve setting which will be approximately 50 pounds.
| The lubricating oil pressure is not adjustable. The operating pressure range is determined by such things as manufacturing tolerances, oil temperature, oil dilution and, of course, engine speed. Thus no specific operating pressures can be given. Generally however, the lubricating oil pressure will be between 16 to 25 pounds at idle speed of 275 RPM and 30 to 50 pounds at full speed of 800 to 835 RPM. A lubricating oil pressure gauge, Fig. 4-10, is mounted on the engine control panel. The minimum pressure at idle is 6 pounds and at full speed is 20 pounds. Operation at pressures above these minimums is entirely satisfactory. A low oil pressure shutdown device built into the governor protects the engine against low engine oil pressure or high vacuum on the suction side of the pressure lubricating oil pump. In the event of insufficient oil pressure, the shutdown feature will automatically protect the engine by causing it to stop. |
|---|
Schemetic Of Fuel Oil System -- Fig. 4-11
A schematic diagram of the fuel oil system is shown in Fig. 4-11. Fuel is drawn from the storage tank through the suction side of the dual fuel filter by the motor driven gear type fuel pump. From the pump the fuel is forced consecutively through the pressure side of the dual fuel filter and the sintered bronze filter. After passing through the double element sintered bronze filter the fuel flows to the injectors. The excess fuel not used by the injectors returns to the fuel tank through the return fuel sight glass, mounted on the sintered bronze filter housing. An orifice restricts the flow of fuel into the glass and causes a slight back pressure of fuel on the injectors. By maintaining a slight back pressure on the injectors a posive supply of fuel for the injectors is assured.
The fuel pump delivers more fuel to the engine than is burned in the cylinders. The excess fj.iel circulated through the injectors is used for cooling and lubricating the fine working parts of the injectors.
A 15 pound relief valve is built around the pressure side of the dual fuel filter. This relief valve bypasses fuel to the sintered bronze filter if the element in the pressure side of the dual filter becomes clogged.
408 Fuel Sight Glasses Mounted on the sintered bronze filter housing are two sight glasses, Fig. 4-12.
 Sight Glasses -- Fig. 4-12 | For proper engine operation, a good flow of fuel (clear and free of bubbles) should be indicated in the sight glass nearest the engine called the "fuel return sight glass." With no fuel showq ing in the fuel return sight glass, check to see that fuel pump motor is running. If motor is running and no fuel is flowing in eturn sight glass, check (a) fuel supply in fuel tank (b) position of emergency cutoff valve (c) clogged suction filter (d) suction leak in piping between tank and pump or (e) broken or slipping coupling at fuel pump. |
|---|
If fuel pump motor is stopped, check (a) "Control and Fuel Pump" circuit breaker must be "ON" (b) "Fuel pump" circuit breaker in electrical cabinet must be `ON" (c) control knife switch must be closed (d) main battery switch must be closed or (e) loose fuel pump motor cable connection.
The sintered bronze filter is also equipped with a 15-pound relief valve and sight glass, Fig. 4-12. This sight glass is referred to as the "45-pound sight glass" and is normally empty. When more than a trickle of fuel is seen in the 45-pound sight glass, it indicates that the relief valve is open. Fuel will pass through the 45-pound sight glass and relief valve to by-pass the engine and return to the fuel tank in case the sintered bronze filter becomes clogged.
409 Filling Fuel Tanks The fuel tank can be filled from either side of the locomotive. A short sight .evel gauge is located next to each fuel filler. This fuel gauge indicates the fuel level from the top to about 4-1/2" below the top of the tank and should be observed while filling the tank to prevent overfilling. DO NOT HANDLE FUEL OIL NEAR AN OPEN FLAME.
410 Fuel Gauge The basic fuel capacity is 900 gallons. Full length sight level gauges are located on each side of the front end of the fuel tank. These gauges indicate the level of fuel in the tank below the low level of the short fuel filler gauge.
411 Emergency Fuel Cutoff Valve An "Emergency Fuel Cutoff Valve," Fig. 4-13, is provided to cut off the fuel supply to the fuel pump in the event of fire, or any emergency. It is located inside a compartment on the lower front center of the fuel tank. On each side of the locomotive is a small box with a lift cover. Enclosed in this box is a pull ring on the end of the cable running to the fuel cutoff valve. A similar ring is located in the cab of the locomotive.
The fuel cutoff valve can be tripped by pulling any one of these three rings. If tripped, the valve must be reset manually.
To reset the valve, "push in" on the rod extending from the valve compartment on the right side of the locomotive.
Compressed air is required on a Diesel locomotive for operation of the air brakes and sanders. In addition to this such items as the shutter operating cylinder, horn, bell and windshield wipers are also air operated. Some of the items mentioned are merely electro-pneumatic valves. This means that in such cases the flow of air, through the valve, is controled by electrical circuits.
112 Air Compressor Each locomotive power plant is basically equipped with a water cooled 3-cylinder, two stage air compressor, Fig. 4-14. The air compressor is driven through a flexible coupling, from the front end of the engine crankshaft.
The compressor has its own oil pump and pressure lubricating oil system. The oil level in the compressor crankcase is shown in a sight glass on the side of the compressor. The oil level may be checked with the engine running or shut down, and should be at or near the full mark.
The compressor consists of two low pressure cylinders and one high pressure cylinder. The pistons of all three cylinders are driven by a common crankshaft. The two low pressure cylinders are set at an angle to the vertical high pressure cylinder. Air from the low pressure cylinder goes to an intercooler, to be cooled before entering the high pressure cylinder.
The intercooler is provided with a pressure gauge and relief valve. The gauge normally reads approximately 45 to 50 pounds when compressor is loaded. The intercooler relief valve is set for 65 pounds. Any marked deviation of intercooler pressure should be reported.
It is recommended that the compressor intercooler (two drain valves are provided in the bottom header) and the main reservoirs be drained at the regular maintenance period, to prevent moisture and dirt from being carried into the air brake and other air systems.
413 Compressor Control Since the air compressor is directly connected to the engine, the compressor is in continuous operation (although not always pumping air) whenever the engine is running. An unloader piston is provided in the head of each high and low pressure cylinder which cuts out the compressing action when actuated by air pressure from the compressor governor control. The unloader accomplishes this by blocking open the intake valves of the high and low pressure cylinders. When the air operating the unloader is cut off, the unloader releases the intake valves and the compressor resumes pumping. Main reservoir air pressure is used to actuate the unloader valves.
 Pneumatic Governor Control System -- Fig. 4-15 | Two methods of compressor governor control are used: (1) Pneumatic
governor control and (2) Electro-pneumatic governor control.
On locomotives with the pneumatic governor control system, Fig. 4-15, each air compressor operates as an individual component without regard to the main reservoir demands of other units in the consist. |
|---|
When the main reservoir air pressure reaches 140 pounds, the governor "cuts out" the air compressor by admitting air to unloader valves. Admitting air to the unloader valve will hold the intake valves open stopping the compressing action. The compressor remains unloaded until the main reservoir pressure falls to 130 pounds. The governor then "cuts in" the air compressor by stopping the air supply to the unloader valves, releasing the intake valves and the compressor resumes pumping.
If all the units of a locomotive consist are equipped with the electro-pneumatic system of compressor governor control, Fig. 4-16, the electrical arrangement is such that all compressors in the locomotive are synchronized to pump air into their respective main reservoirs when the main reservoir pressure in any one unit drops to 130 pounds. When the air pressure in all reservoirs reaches 140 pounds, the compressors will unload. Each unit is equipped with a compressor control switch (CCS) actuated by main reservoir pressure, a compressor control magnet valve and a compressor relay (CR). A compressor control wire (CC) runs throughout the locomotive and connects the compressor relays in each unit in parallel.
This electro-pneumatic governor control is located on the equipment rack supporting the water supply tank, oil cooler and Michiana filter assemblies, Fig. 4-17. The compressor control switch may be considered to be a single-pole double-throw switch that is thrown to the "loaded" position when the main reservoir pressure drops to 130 pounds, or to the "unloaded" position when the main reservoir pressure reaches 140 pounds. In the unloaded position the CCS causes the compressor control magnet valve to be energized, allowing air to pass through the valve to the compressor unloader pistons stopping the compressing action. In the loaded position the CCS breaks the circuit to compressor control magnet valve in that unit and causes current to flow through the CC wire energizing all the CR relays.
When the CR relay is energize its interlock breaks the circuit to the compressor control magnetic valve regardless of the position of the CCS in that unit. Breaking the circuit to the compressor control magnet valve shuts off the supply of air to the compressor unloader pistons, and the compressor resumes pumping.
414 Manual Unloader Valve A three-way valve, Fig. 4-15 or Fig. 4-17, is provided in case it is desired to keep an air compressor unloaded,irrespective of the compressor control system. A raised "T" pattern on the face of the valve indicates the flow of air through the valve. The valve is normally positioned so as to direct the air supply to the unloader valves through the compressor governor control. To manually unload the air compressor, turn valve to bypass main reservoir air supply to the unloader valves around the compressor governor control.
415 Draining Of Air System The air system should be drained periodically to prevent moisture from being carried into the air brake and other air systems. The frequency of draining will depend on local conditions and can be determined by practice. It is recommended that draining be done at the time of each crew change, until a definite schedule can be determined by the individual railroad.
