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51 Cards in this Set
- Front
- Back
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What are the 5 main control systems of a locomotive? |
The Diesel Engine. The Fuel System. The Lube Oil System. The Cooling System. The Electrical Systems. |
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What should be done before starting any locomotive? |
Knife Switch In. Genfield Off & Park Brake applied. Switch in Start. Check log book for defects/failures that may affect locomotive engine running. Check there are no safety or do not operate tags. Turn on appropriate circuit breakers. Check Oil & Coolant levels. |
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How many horsepower do Locos commonly used by PN Melbourne Intermodal have? |
Class - Total HP/HP Available for tractive effort. NR - 4000/4000 93 - 4350 LDP/TT - 4490/4300 AN - 4000/3836 G - 3300/3000 81 - 3300/3000 82 - 3250/3000 XR - 3300/3000 |
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What is de-energized when a penalty brake application occurs? |
Locomotive's control circuit. |
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The main components of a Locomotive can be classified into 3 groups. What are they? |
Bogie components. Underframe Components. Equipment Compartment Components. |
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List some components found on a loco bogie? |
Wheels & Axles, Brake Rigging, Brake Blocks, Sanding Equipment, Brake Pistons, Traction Motors, Bearings, Shockers, Springs, Snubbers, Side Frames, Bolster. |
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List some components found on a loco underframe. |
Fuel tank, battery box and batteries (most classes), bogies, couplers and draft gear, isolating cocks, main reservoirs. |
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In short how does a diesel electric loco work? |
The diesel engine supplies mechanical energy via the crankshaft to the traction alternator. The Tractional Alternator coverts mechanical energy in to electrical energy. The electrical energy is delivered to the traction motor via the propulsion system. The Traction motors convert the electrical energy back to mechanical energy which is delivered to the axles via a pinion gear on the end of the armature shaft and a main gear wheel located on each driven axle. |
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How are burnt gases exhausted from the cylinders to atmosphere? |
Burnt gases expelled through exhaust valve in to an exhaust manifold. Exhaust flow under pressure in to the turbocharger then through mufflers to atmosphere through exhaust stack. |
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How can you identify defective exhaust valves? |
Sticking or defective valves can be identified by an unusual sounding (off beat) exhaust and excessive black smoke. |
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How can observing exhaust stack smoke help identify engine problems? |
Black Smoke usually indicates fuel problems (blocked injectors, fuel or air filters). White Smoke usually indicates burning oil because of mechanical faults, defective exhaust valves or worn piston rings. Pluming - exhaust clears every few seconds between smoke emissions. |
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What is the function of the crankcase? |
Forms the main structural part of the engine, it contains the crankshaft and oil pan (sump). Should operate with a slight negative pressure. |
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Positive crankcase pressure means a serious problem has developed, what can cause positive crankcase pressure? |
Compression leak in to crankcase due to worn or broken piston rings. Internal engine component failure. Blocked lube oil separator. Excessive Oil in Sump. Crankcase explosion due to ignition of lube oil vapour. |
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What is the function of test cocks/cylinder relief valves? |
One for each cylinder, used to drain water from cylinders if hydraulic lock is detected. Never open when diesel engine is running. (To open turn 3 times anti-clockwise EMD, clockwise GE). |
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Should an engine be running to check the lube oil level? Why? |
Yes, oil is flowing through engine and components giving a truer reading. Dipstick level can be up to 75mm higher if oil is checked when engine is shutdown. |
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Where is the lube oil cooler found? |
NR - Co-driver's side between engine & compressor, floor level. EMD - Equipment Rack between engine and compressor. The rectangular component between the two cyclinders (header tank and oil filters. |
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What is the purpose of the oil cooler? |
Cooler consists of a small radiator with engine cooling system water flowing through it. Cools oil from the diesel engine before it enters the oil filters. |
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Where are the lube oil filters found? |
NR - Driver's side between engine and compressor at floor level. EMD - Equipment rack between engine and compressor. Cylinder at ground level (below cooler and header tank). |
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What is the function of the lube oil separator? |
Powered by suction pressure from turbo the lube oil separator removes crankcase gases and oil vapours. Oil drains back in to sump, gases are passed on to the exhaust system. EMD - right hand side of turbo. NR - Internal component. |
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What are the main components of the cooling system? |
Radiators, Cooling Fans, Water Pump(s), Header Tank, Lube Oil Cooler, Engine Protector (EMD). |
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What would you look for when checking the cooling system? |
Coolant Sight Glass, Cooling fan operation, abnormal noise, water leaks from components, piping and joints, temperature gauge. |
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What determines how fast a water pump orperates? |
Operates in proportion to the diesel engine speed. |
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What are strokes of a 2 stroke engine? (EMD) |
Downward - Power Stroke. Combustion of Air & Fuel. Upward - Compression Stroke. Air is injected at bottom of power stroke, fuel is injected at top of compression stroke to ignite and initiate power stroke. |
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What are the strokes of a 4 stroke engine? (GE) |
Down - Air in to Cylinder. Up - Compression Down - Fuel in to cylinder, Power Stroke/Combustion Up - Exhaust |
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!!! What are the main components of the fuel system? |
Tank, Pump, Filters, Sight Glass(es), Fuel Lines, Injectors, Injector pumps (NR), |
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If the engine stop button fails to operate what are some ways the diesel engine may be shutdown? |
Try other shutdown buttons, trip fuel pump circuit breaker if all else fails and loco needs to be shut down. EMD - pull layshaft back to no fuel position or emergency shutdown button. Drain engine protector valve, lift throttle back beyond idle to shutdown (26L types), pull out low oil shutdown plunger in governor. |
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How long should the fuel prime be used before attempting to start? |
EMD - 15 seconds. NR - Until fuel pressure light goes out. |
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If the gen-field switch is off what is isolated? |
Load Regulator from 74V Control Circuit (EMD). Traction Alternator output. |
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What is it called when an engine speed becomes erratic and what may cause it? |
Hunting.
Blocked injector(s), Blocked fuel filters, erratic fuel pump speed, loose governor cable (EMD). |
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Which engines have engine protectors? |
EMDs. (Except LDP & TT)
NR & 93's are protected by microcomputers. |
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Loco Batteries provide 64Volt DC current to low voltage circuits, which devices operate using this current? |
Headlights, Auxiliary Lights, Fuel Pump (when engine is not running), turbo lube pump, pre-lube pump, starting circuits & start motors, communication equipment. |
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!!! Where is the battery box found on common classes of loco? |
NR - underframe driver's side (5 doors) AN & 81 - Underframe, A/No 1 End of Fuel Tank G & BL - Engine Room compartment number 1 end. |
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What is the function of the Battery Knife Switch? |
Isolates the batteries from Loco's low voltage circuits. Must be closed when engine running & opened when shut down. |
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What recharges the batteries when a loco is running and how can this be checked? |
Auxiliary Alternator (all locos). EMD - Battery Charge Ammeter beside Engine stop button. NR - 2028 on DID panel, a "No Battery Charge" message will display if there is a problem. |
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All locomotive electrical circuits are described as what? |
Above ground circuits. Meaning current flows from positive terminal of power source to an electrical device then return through the negative terminal to power source without going to ground. |
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What is a low voltage ground? |
If any of the Battery's low voltage current (pos or neg) flows to the locomotive frame. Can be caused by defective contactor or relay, loose or worn wiring or moisture. |
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What is a low voltage ground? |
If any of the Battery's low voltage current (pos or neg) flows to the locomotive frame. Can be caused by defective contactor or relay, loose or worn wiring or moisture. |
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What is the function of the Traction Alternator? |
The traction alternator connected to the crankshaft spins at engine speed with field winding excited by companion (EMD) or auxiliary alternator(GE). Produces high voltage AC current up to 7000amps which is converted to DC by a rectifier to power traction motors. |
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What 3 conditions must exist for the Traction Alternator to procude high voltage current for traction purposes? |
Rotor turned by diesel engine, rotor's field winding are excited, high voltage circuits to traction motors are complete. |
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What protects the traction alternator field windings from overload? |
Gen Field circuit breaker. |
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What is the difference between 'Parallel' and 'Series Parallel'? |
Parallel means that each of the loco's traction motors has it's own circuit recieving 1/6 of the traction alternator output. Series Parallel means traction motors are grouped in to 3 sets of 2. |
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Most PN locos use Parallel circuits for traction motor groupings, which don't? |
XR, XRB, C (under 50kmph) |
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How many power contactors do NR, AN, G, 81 classes have? |
6. P1-P6.
Note - 6 for Parellel, 1 for each traction motor. |
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What are some things to check for if a loco isn't powering? |
Isolation switch, engine control switch, gen field & engine run switches, circuit breakers (control, local control, gen field, aux gen x2 EMD etc.), CA4 door (NR), DID Panel, engine control panel switches, Brake Pipe reading (PKS). |
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What is the engine run circuit? |
Connects the throttle to the Governor (EMD) to allow the engine to respond to throttle movements. (Microcomputers NR). When the Engine run switch is switched off the engine speed will return to idle. Loco can still power but engine speed will not increase meaning only the equivalent of notch 1 will be available. |
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How does the control circuit work? |
Provides low voltage current to fuel pump, control & FP switch (EMD), engine run switch, local control circuit, vigilance control circuit, alarm circuit & starting circuit. Current is supplied by Aux Alternator or batteries when shut down. Circuit is train lined.
If tripped engine returns to idle and will not respond to throttle. Shuts down (EMD) and a penalty brake application will occur (except NR). |
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What is the Local Control Circuit? |
Connects the 74V Low voltage supply between Aux Alternator and High Voltage switch gear and other electrical components. Circuit breaker must be in the ON position for loco to operate, not a train lined function.
Power contactors, reverser switch, comp/aux alternator excitation (EMD/GE), dynamic brake control, auxiliary low voltage circuits. |
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If the local control circuit breaker is tripped will the loco shutdown? |
G,BL & 81 will shut down, other types will not respond to throttle and engine return to idle. |
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What is the function of the generator field switch? |
When switched on the excitation circuit to the traction alternator is completed. Off - No traction amps but engine will respond to throttle. |
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How does the Ground Relay work? |
Operates when high voltage leakage is detected in the loco frame. It will remove traction alternator or dyno output return engine to idle and initiate an alarm & fault light/message. Only removes output on affected unit in multi-unit operation. Note - GE Locos don't have "a ground relay" they have 'Ground Detection Circuits'. |
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What does the ground relay protect? |
Traction Alternator, Companion Alternator, Propultion circuits and wiring, Power Contactors, Traction Motors, Dyno Circuits & wiring, Dyno contactors and blowers. |
