Patent Number: 
Section: claims

1. A method for identifying one or more malfunctions from a plurality of malfunctions that can occur in a locomotive air compressing system comprising a plurality of components, with at least some of said plurality of malfunctions being correctable onboard a locomotive, said at least some malfunctions constituting onboard serviceable malfunctions, while a remaining of said plurality of malfunctions are correctable with the air compressing system being uninstalled and serviced at an off-board servicing site, said remaining malfunctions constituting off-board serviceable malfunctions, said method comprising:performing a test sequence configured to isolate components of the air compressing system from one another to identify a component subject to a malfunction;applying a pressurizing stimuli to the isolated components;monitoring a response indicative of a malfunction type, the malfunction type being associated with one of the following: a corrective action to be performed onboard the locomotive, and a corrective action to be performed off-board the locomotive; andperforming the corrective action appropriate for the malfunction type. 2. The method of claim 1 further comprising performing a crankcase inspection prior to performing said test sequence, and determining whether or not predefined criteria for passing said crankcase inspection is met, and, if said crankcase inspection meets the predefined passing criteria, proceeding to perform the test sequence. 3. The method of claim 1 wherein said air compressor system comprises a high-pressure stage and a low-pressure stage and performing the test sequence comprises isolating the low-pressure stage from the high-pressure stage to identify a malfunction likely to correspond to a respective one of said stages. 4. The method of claim 3 wherein said low-pressure stage comprises at least one low-pressure cylinder and at least one intercooler coupled to the low-pressure cylinder and wherein the applying of the pressurizing stimuli comprises pressurizing through an inlet port said least one low-pressure cylinder and said at least one intercooler. 5. The method of claim 4 wherein the monitoring of a response indicative of a malfunction type comprises monitoring a depressurization rate of the pressurized said at least one low-pressure cylinder and said at least one intercooler. 6. The method of claim 5 further comprising comparing the monitored depressurization rate relative to a predefined depressurization rate limit, and identifying a likely malfunction type based on the results of said comparison. 7. The method of claim 4 wherein the monitoring of a response indicative of a malfunction type comprises visually monitoring said at least one intercooler to detect an air leak in the intercooler, and, in the event said intercooler air leak is identified, replacing said intercooler onboard the locomotive. 8. The method of claim 4 wherein the monitoring of a response indicative of a malfunction type comprises monitoring air flow through an oil-filling port in a crankcase, and wherein a sensing of said air flow is indicative of a leak through a wall of said at least one low-pressure cylinder, and, in the event said air flow is sensed, performing a compressor removal from the locomotive for performing a compressor overhaul at the specialized servicing site. 9. The method of claim 3 wherein said high-pressure stage comprises a high-pressure cylinder and an aftercooler coupled to the high-pressure cylinder and wherein the applying of a pressurizing stimuli comprises pressurizing through an outlet port said high-pressure cylinder and said aftercooler. 10. The method of claim 9 wherein the monitoring of a response indicative of a malfunction type comprises monitoring a depressurization rate of the pressurized high-pressure cylinder and aftercooler. 11. The method of claim 10 further comprising comparing the monitored depressurization rate relative to a predefined depressurization rate limit, and identifying a likely malfunction type based on the results of said comparison. 12. The method of claim 9 wherein the monitoring of a response indicative of a malfunction type comprises visually monitoring said aftercooler to detect an air leak in the aftercooler, and, in the event said aftercooler air leak is detected, replacing said aftercooler onboard the locomotive. 13. The method of claim 9 wherein the monitoring of a response indicative of a malfunction type comprises monitoring air flow through an oil-filling port in a crankcase, a sensing of said air flow being indicative of a leak through a high-pressure cylinder wall, and, in the event said air flow is sensed, performing a compressor removal from the locomotive for performing a compressor overhaul at the specialized servicing site. 14. The method of claim 9 wherein the monitoring of a response indicative of a malfunction type comprises sensing air flow through an intake port of the high pressure cylinder, a sensing of said air flow being indicative of a leak through a high-pressure cylinder wall being indicative of at least one malfunctioning valve in the high pressure cylinder, and, in the event said air flow is sensed, performing a cylinder head replacement onboard the locomotive for the high pressure cylinder. 15. The method of claim 1 wherein the applying of pressurizing stimuli comprises pressurizing a crankcase and the monitoring of a response indicative of a malfunction type comprises monitoring a depressurization rate of the pressurized crankcase, said crankcase pressurizing and monitoring avoiding removal of a compressor motor for gaining visual access to crankcase seals wherein leakage is likely to develop. 16. The method of claim 1 wherein the applying of pressuring stimuli comprises energizing a compressor motor at a predefined RPM and monitoring a volume of pressurized air actually delivered by said compressor system over a period of time, and comparing the volume of pressurized air delivered by the compressor system relative to a predefined range indicative of whether or not said air compressor system meets a specified air-compressing capability. 17. The method of claim 16 further comprising monitoring an intercooler pressure and comparing said intercooler pressure relative to predefined pressure values to determine occurrence of a likely malfunction in one of the following: a cylinder head of a high-pressure stage and cylinder heads of a low-pressure stage of said compressor system. 18. A method for identifying one or more malfunctions from a plurality of malfunctions that can occur in a vehicular air compressing system comprising a plurality of components, with at least some of said plurality of malfunctions being correctable onboard a self-propelled vehicle, said at least some malfunctions constituting onboard serviceable malfunctions, while a remaining of said plurality of malfunctions are correctable with the air compressing system being uninstalled and serviced at an off-board servicing site, said remaining malfunctions constituting off-board serviceable malfunctions, said method comprising:performing a test sequence configured to isolate components of the air compressing system from one another to identify a component subject to a malfunction;applying a pressurizing stimuli to the isolated components;monitoring a response indicative of a malfunction type, the malfunction type being associated with one of the following: a corrective action to be performed onboard the vehicle, and a corrective action to be performed off-board the vehicle; andperforming the corrective action appropriate for the malfunction type.