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30 INTRODUCTION Three case studies were selected from the survey results to provide more in-depth examples of PM programs. Person- nel directly involved with these programs agreed to be inter- viewed by telephone. In some cases, more than one person at an agency participated in the interviews. Case studies were selected because of PM features of interest and use to other agencies. WTA in Washington State was selected to review its technician certification program that requires all technicians to perform PM activities in a like manner according to agency-established requirements. WMATA was chosen because of its innovative onboard monitoring system that automatically downloads fault data as buses enter the service line. A case study was also made of the PM challenges faced by Centro, which operates nearly 300 buses with 23 different classifications using 21 different PM schedules. WHATCOM TRANSPORTATION AUTHORITY Introduction WTA was selected as an example of a smaller agency (fewer than 100 buses) that has taken proactive measures to improve its PM program. The agency has instituted a Technician Certification Program for conducting PM inspections. In addition to visually examining buses, WTA requires techni- cians to take measurements and conduct tests of certain com- ponents and systems to more accurately represent equipment condition. The Technician Certification Program was ini- tiated to ensure that all technicians approach safety-critical inspections with the same level of understanding and abilities. The agency is also investigating whether to involve its infor- mation technology (IT) department in the PM of intelligent transportation system (ITS) equipment. Agency Overview WTA is the public transit provider for Whatcom County, Washington, operating both full-size and paratransit buses. WTAâs service area encompasses approximately 840 square miles, logging about 4.9 million boardings and 2 million miles annually. Fixed-route transportation services are provided by 56 full-size buses, and paratransit services include 40 acces- sible 15-passenger buses. WTAâs fixed-route maintenance was performed by the city of Bellingham Public Works Department; smaller buses and support vehicles were maintained by two WTA technicians, with most work being out-sourced. In 2002, WTA moved into a new facility and broke its contractual ties with the city regarding vehicle maintenance. The first change was to bring maintenance work back in-house. The second was to bring the PM program back under the agencyâs control. After seven years of continual improvement, WTAâs current PM program bears little resemblance to the cityâs original operation. Preventive Maintenance Program Review WTA uses a 4,000 mile PM interval for its paratransit buses and a 6,000 mile interval for full-size buses. The agencyâs PM program is constantly evolving, using OEM specifications as a base supplemented by actual agency experiences and input from technicians. The MIS generates a unique inspection sheet for each bus, based on bus make, model, and age; mileage interval; previous work history; items deferred from the last PM inspection; and other inspection items requiring special follow-up attention based on a previous repair or inspection. Any defects that get repaired are itemized separately from routine inspection tasks, allowing parts and labor costs to be tracked under separate categories. WTA has a specific policy regarding repair of defects noted during the PMI. If the defect is safety-critical or prevents the PM from being completed the defect gets repaired immedi- ately. Otherwise, QA personnel on the shop floor prioritize which defects get repaired. Deferred repairs automatically appear on the next PM sheet generated by the MIS. Work orders remain open until the defect is repaired. The main- tenance manager reviews all open work orders daily. The agencyâs policy, however, is get as much done as possible while the bus is in the shop. Technician Certification Program After gaining control of its maintenance operation WTA real- ized it needed a formal Transit Technician Certification Pro- gram where all technicians would carry out safety-sensitive maintenance tasks in a manner prescribed by the agency. The ten safety-sensitive systems and components identified by WTA are: CHAPTER FIVE CASE STUDIES
31 1. Service and Parking Brake 2. Air System 3. Steering System 4. Suspension and Undercarriage 5. Tires, Wheels, and Wheel End Components 6. Exterior Lights, Mirrors, Signals, Wipers, and Warning Devices 7. Fuel and Exhaust Systems 8. Interlock Systems 9. Interior Lights, Gauges, Warning Devices, Controls, and Safety Equipment 10. Wheelchair Lifts. According to WTA, the ten areas represent the bulk of systems and components that if not properly inspected and maintained have the largest propensity for causing vehicle accidents and/or passenger injuries. A training and certification program was especially needed for PM inspections because technicians were hired with diverse fleet experience. Lacking direction from the agency, each technician performed inspections differently. Standards were needed to establish how PMs were conducted, defects were identified, and follow-up repairs were made. An important step in establishing job consistency was to develop a task list of 75 inspection items. Next was to establish procedures that clearly identified what technicians looked at during a PMI and conditions under which items are serviceable and when they need to be replaced. Inspection criteria were determined using OEM manuals and service bulletins, DOT regulations, Technology and Maintenance Council (TMC) suggested practices established by the ATA, and other available reference materials. In areas where there was no clear published standard, a standard was established based on agency experiences. Under WTAâs Certification Program technicians must demonstrate the ability to carry out safety-critical PM inspec- tions and repairs. WTA hires technicians as skilled journey- men and requires them to work side by side with experienced agency technicians to learn how to perform specific tasks to established WTA procedures. Each technician is given a series of tasks and must successfully carry them out under the supervision of a lead technician who serves as a Task Administrator. Passing the Certification Program is entirely hands-on, with no written test. If a task is not successfully completed, additional training is provided until the task is mastered. Tasks in all ten safety-critical areas must be suc- cessfully completed before a technician receives certification, and every technician is expected to be certified. A spreadsheet is used to track each technicianâs progress. The Technician Certification Program takes up to two months to complete. Training is provided in each of the ten safety-sensitive task areas, conducted by lead technicians and supervisors using service manuals and training videos. Limited off-site instruction is also provided, with technicians experienced in certain areas providing targeted training. Because many of the new hires are former truck technicians, training is primarily intended to help in the understanding of unique bus aspects and in becoming familiar with WTA shop procedures. A key outcome of the program is that technicians conduct PM inspections in a consistent manner where they are required to measure and test many safety-critical systems and components instead of simply checking them off. Technicians receive a certificate upon successful comple- tion of the program, along with a shoulder patch that is sewn on to their uniform. The patch is shown in Figure 5. Improved Maintenance Performance WTAâs Technician Certification Program produced some ini- tial challenges as both labor and management had to adapt to new leadership, working conditions, and work procedures. Once resolved, the agency experienced significant improve- ments in the form of a reduced number of road calls and ser- vice interruptions. To track road calls the agency moved to a Vehicle Maintenance Reporting Standards (VMRS) system. VMRS was developed as a standardized coding convention for tracking equipment assets and maintenance repairs by the TMC of the ATA. Although transit is required by the FTA to report service interruptions according to definitions identified as part of the National Transit Database, many agencies such as WTA also use VMRS coding to more accurately classify road calls. FIGURE 5 WTA technician certification program patch.
32 Since instituting its Certification Program WTA has elim- inated or reduced road calls in several key areas. ⢠Eliminated âhot wheelâ road calls and malfunctions related to wheel bearing torque and adjustment proce- dures. A new WTA procedure specifically calls for technicians to follow the TMC Recommended Practice for bearing adjustment, which requires them to use a dial indicator and follow precise instructions. Before that a front wheel had come off a bus because the wheel bearing overheated and failed from improper adjustment. ⢠Reduced brake-related road calls and malfunctions. The Certification Program trains technicians to use mea- suring tools such as âgo/no-goâ gauges, spider gauges, dial indicators, and other brake component measuring tools to document brake wear. Brake components are now replaced because a technician measured and found tolerances outside specification limits. Previously, tech- nicians would change out every single brake compo- nent, good or bad, just because it was done that way in the past. ⢠Reduced air system-related malfunctions. A procedure to inspect and test air compressors, especially with 2007 engines where the air compressor inlet is located just below the EGR outlet, reduced the number of road calls resulting from insufficient air pressure. The agency found soot and engine exhaust residue in the air system and was able to take action by notifying the bus OEM that vehicle air system components were being con- taminated and damaged by engine exhaust residue coming from the air compressor. Although this issue was actually an engine manufacturerâs problem, WTA impressed upon the OEM that this problem may have safety implications if not corrected. WTA insisted that the engine OEM identify the exhaust contamination source, causing the OEM to respond with a campaign to re-route the air compressor inlet further upstream from the EGR to prevent exhaust gases from entering the air compressor inlet. ⢠Eliminated tire, wheel, and wheel-end-related road calls. New procedures direct technicians to pay closer attention to tire wear indicators. WTA purchased a portable alignment system and now schedules buses for alignments when technicians note abnormal tire wear patterns. ⢠Reduced exhaust system-related road calls. Technicians are trained to identify abnormal DPF system conditions and resolve potential problems before they result in a road call. ⢠Eliminated wheelchair lift and ramp-related road calls. Four technicians were sent to factory training classes and returned to train other WTA technicians. Trained technicians then developed PM tasks and training for the wheelchair lift portion of the Certification Pro- gram. PM inspections now include extensive lift and ramp checks. Preventive Measurement Program Refinements WTA constantly reviews unscheduled maintenance events and enhances its PM program in a proactive manner to help reduce future occurrences. All maintenance employees are encouraged to provide input into PM checklist tasks, how PMIs are conducted, and the intervals at which PM activities take place. Following are some of the refinements made to improve the PM program as a result of the collaborative participation: ⢠Added an in-depth door inspection procedure in response to safety concerns. ⢠Added brake system inspections to test air system alarms and valves. ⢠Added procedure to inspect turbochargers on higher- mileage buses to prevent turbocharger failures and result- ing damage to exhaust after-treatment devices. ⢠Added procedure to torque oil drain plug to prevent over-tightening and resulting oil pan damage. ⢠Added in-depth brake inspections. Brake drums are removed and foundation brakes inspected and S-cam wear checked to ensure all brake components are in serviceable condition. Particular attention is paid to environmental factors that contribute to brake wear and malfunctions such as water, sand, and salt intrusion. ⢠Enhanced wheelchair lift and ramp inspections and ser- vicing based on specialized training provided by the OEM. Many of the road calls in the past were the result of incomplete inspections and servicing. ⢠Added air compressor tests to detect oil and soot con- tamination, and to check settings. ⢠Added sampling of hydraulic oil to reduce hydraulic pump failures on older buses. ⢠A âBowmonk BrakeChekâ tester is used during the road test portion of every PM regardless of vehicle size or application to verify braking system performance. All results are documented. Testing has identified poor brake performance that otherwise would not have been identified by only conducting a visual inspection. ⢠Purchased new wheel lug nut torque tools and added pro- cedures to eliminate broken wheel studs caused by over- tightening lug nuts. Pneumatic torque wrenches stall once lug nuts reach correct torque settings. The agency has not experienced a broken wheel stud or loose lug nut since purchasing the new tools. The addition of new procedures and tools is designed to get technicians to take more measurements during PM. The new procedures require technicians to initial (rather than simply â) every PMI check on the checklist to foster a sense of âownershipâ for each PMI checklist item. Fortunately, the agency has not had any serious accidents or fatalities; how- ever, if one does occur the agency can produce documentation showing that vehicles were inspected to a consistent stan- dard, measurements were taken, tests conducted, and results documented to prove the bus was in safe operating condi- tion following inspection.
33 Quality Assurance To make certain PM inspections are done to agency standards lead technicians also work as QA inspectors. They check three or four items at random during each PMI. If measure- ments taken during the random QA inspection do not match, the technician is asked to re-measure. The QA inspector gets to know the capabilities of technicians and provides instruc- tion when needed. A QA stamp is used when inspections are done correctly. Intelligent Transportation System Equipment WTA, as with many other agencies, is experiencing unprece- dented growth in the number of ITS devices intended to pro- vide increased passenger information, safety, and security. Examples of onboard ITS equipment includes AVL, auto- matic next-stop annunciators, video surveillance cameras, traffic signal preemption, and others. Although this equip- ment has done much to improve transitâs image and inte- grate it with other transportation modes, it rarely affects the physical operation of the bus such as the engine or braking system does. Given the complexities of ITS, WTAâs maintenance depart- ment finds it difficult to keep pace with the training required to properly diagnose, maintain, and repair this equipment along with the various communication protocols that integrate them. The extra work load also creates a dilemma as to which failed equipment gets repaired firstâITS or foundation bus equipment? The proliferation of ITS equipment also adds to the PM workload. Because WTAâs IT department has a good understanding of ITS equipment, the agency is considering a program that involves them in the PM process. Getting the IT department involved allows them to more fully understand maintenance requirements for ITS equip- ment. Input is expected to help WTA prioritize its overall maintenance needs with those of the IT department. WASHINGTON METROPOLITAN AREA TRANSIT AUTHORITY Introduction WMATA was selected for this case study because of its inno- vative approach to downloading data at the service line by means of wireless communication as buses return from rev- enue service, and the use of onboard speakers to give verbal commands to personnel regarding faults that need immediate attention. The system also provides an itemized report of all vehicle faults, allowing the maintenance department to prior- itize repairs. Early identification of faults on a daily basis through expanded onboard monitoring allows the agency to respond more quickly with PM action, which typically would not take place until the next scheduled PM interval or after a sudden breakdown occurred. Agency Overview The bus operation at WMATA, known as Metrobus, pro- vides service to the nationâs capital 24 hours a day, 7 days a week, with 1,500 buses logging about 134 million trips annually. WMATA serves a population of 3.4 million within a 1,500-square-mile jurisdiction. The agency operates approx- imately 460 CNG buses and 50 hybrid buses, with 200 more in the process of being delivered. Background In 1995, WMATA began searching for a method of communi- cating bus stop, route, and transfer information to meet ADA requirements. After testing, the agency selected an Automatic Voice Annunciation System manufactured by Clever Devices, and installed the system on 264 new buses in 1997. Discus- sions between the two organizations led to expanding the Voice Annunciator to include bus performance and operation monitoring. The first automatic vehicle monitoring (AVM) system was installed on two buses in 1998, and has grown steadily since then as did the number of onboard conditions being monitored. Today, 703 of WMATAâs buses are equipped with AVM, and five of its 10 depots are equipped to down- load service information from those buses. Transfer of all data at the service line is done wirelessly. Automatic Vehicle Monitoring System Description Buses continually monitor, measure, and report the status of critical onboard bus systems and components. Robust onboard data collection is made possible through the SAE J1939 com- munications protocol used by drivetrain components (e.g., engine, transmission, and brakes) to send and receive control commands. For example, if wheel sensors detect that drive wheels are losing traction (i.e., spinning on a slippery surface) a command can be sent to the engine to reduce its speed regardless of driver action. The same J1939 communications network also has the ability to monitor and record various operating conditions or parameters within the system. When certain parameters outside acceptable ranges are detected, the fault is broadcast over the J1939 communica- tions network and stored in memory. Drivers receive a warn- ing light or buzzer if faults are more serious. If a catastrophic failure is about to occur, instructions sent over the J1939 network will automatically reduce the engineâs power or cause it to shut down altogether. Sometimes parameters are exceeded but not severe enough to warn the driver or take drastic action. In these cases, technicians use scheduled PM events to plug diagnostic readers into the communications
34 network to access data that can point to a developing prob- lem. However, instead of accessing the data at PM intervals every 6,000 miles, WMATA with its AVM system now has the benefit of obtaining critical data on a daily basis. Vehicle monitoring systems such as the one used by WMATA are designed to âlisten inâ on communications that take place over multiple onboard systems by means of the J1939 network and can be programmed to report abnor- mal conditions in various ways. One is to broadcast certain faults in real time over the bus radio system to headquarters. Another is to broadcast faults by means of short-range wire- less communications as the bus enters the service lane, the method selected by WMATA. As a bus enters the range of a service line antenna, shown in Figure 6, data are transmitted from the bus to the maintenance department. The AVM system first performs a health check of itself, making sure the monitoring and reporting system is func- tioning. The system then goes through various checks including engine; transmission; heating, ventilation, and air conditioning; door system functionality; and brake pushrod travel, an indication of brake wear. If not within acceptable parameters, the Voice Annuciator portion of the system will make a âmaintenance action necessaryâ announce- ment to the hostler (cleaner) when he or she gets back in to park the bus. Critical faults are flagged, and the control center and maintenance department are both notified to hold a bus from service. Less critical abnormalities appear on a daily exception report delivered to the maintenance manager, which lists every fault code generated by the AVM onboard diagnostic system. Data produced by the system goes to a database where a software product developed by the AVM manufacturer produces a series of reports and e-mail notifications. A sample Exception Summary Report is shown as Appen- dix H. It lists fault codes generated for each bus, the day and time each fault occurred, and provides a description of the fault. In the example provided, Bus No. 2616, a 2005 Orion IV 40-foot with John Deere CNG engine, generated seven differ- ent faults on a given day including engine coolant temperature above 212 degrees, fuel valve fault signal, a nonfunctioning brake actuator at axle #1 left side, natural gas tank pressure input voltage low, and others. None were serious enough to warn the driver, but based on the data provided, WMATA is in a better position to schedule repairs and prevent the escalation of defects into more serious ones. According to WMATA the approximate cost for the AVM system is around $20,000 for each onboard bus monitoring system; cost for wayside equipment was not available. Maintenance of both wayside and onboard AVM equip- ment is provided by the vendor under a service contract with WMATA. Custom Applications For electronically controlled components such as engines, transmissions, and anti-lock braking systems, the task of collecting fault data is somewhat straightforward. How- ever, door systems typically lack electronic control ability. Custom solutions were applied to determine door opening and closing times. Monitoring those signals allows WMATA to determine if a door was taking too long to close or was opening too fast. If so, the AVM system generates a fault code sent to the maintenance department as the bus enters the service line. Understanding that too much information can be over- whelming, WMATA went through a process of determining which faults might trigger a âmaintenance action necessaryâ announcement to service line hostlers. The process involved weeding out unimportant, irrelevant, and even erroneous fault codes, and building in system filters to tighten monitor- ing parameters. In another application, engine temperatures were more closely monitored to prevent overheating. Previously, cer- tain bus engines would overheat because the design of the cooling radiator causes it to clog with debris. When this occurred the engine control system triggered a warning light to the driver, and in more severe cases automatically shut down the engine. WMATA cleaned radiators every day to prevent service failures, knowing that some radiators probably did not require it. Now the AVM system is set up to issue a warning at the service line when the coolant tem- perature is approximately 12 degrees lower than the engine parameter set point. Early warning of rising temperature indicates that the radiator needs to be inspected and cleaned. The early warning now allows WMATA to clean specific radiators only when needed.FIGURE 6 Antenna receives wireless data from WMATA buses.
35 Preventive Maintenance Benefit As stated earlier, critical defects are repaired immediately, whereas those that can wait are typically scheduled for another time or at the next scheduled PM interval. Every day each bus division receives a printout of all faults found on the fleet. Data are reviewed, faults prioritized, and repairs sched- uled accordingly. Senior shop personnel also review past bus histories and conduct trend analysis to determine the exact repair procedures required to correct abnormalities. A detailed work order is then given to the technician, relieving him or her from performing certain diagnostic tasks. All activities are designed to make efficient use of the early warnings pro- vided by the onboard data collection and daily reporting sys- tem. The objective is to prevent initial problems from grow- ing into larger ones that typically require more labor and parts to correct, can potentially cause a safety incident, and result in an in-service breakdown. Service line hostlers could not achieve the same level of fault detection. Indeed, AVM has expedited the service line function because hostlers are relieved from making several of the customary inspections. Combined with those daily inspections that hostlers do make, the automated system greatly contributes to the PM function. Acquiring the same level of daily information would require a skilled technician to perform individual tests on each onboard component and sys- tem. The ability of AVM has also streamlined the PMI func- tion because much of the inspection work is now done by the bus itself. Other Benefits Once a database was established WMATA was able to use the information to develop technical specifications. AVM provides the agency with vast amounts of real world informa- tion that can more accurately define performance require- ments in a bid specification. When specifying door systems, for example, WMATA includes real world data that reflect actual door cycles to ensure the system is robust enough to handle the agencyâs operating environment. WMATA also uses the data for compliance purposes. For example, drivers are required to cycle their wheelchair lifts before beginning service. Based on reports generated by AVM, division superintendents can determine if the daily procedures were indeed followed. WMATA is also saving on warranty claims. For example, when newly delivered buses exhibited a problem with drag- ging brakes, data collected by AVM revealed an engineering flaw that was traced back to the axle manufacturer. The find- ing caused the manufacturer to reline brakes on 250 buses at its own cost. Other trend analyses done with AVM data revealed early problems associated with the fire suppression system caused by faulty engineered sensors and faulty control logic that affected transmission shift quality. Collecting and review- ing data on a daily basis serves as a predictive maintenance tool, allowing WMATA to identify problems early on instead of waiting for the next 6,000 mile PM interval or a breakdown to occur. The manufacturer supplying buses to WMATA also uses the AVM system at its plant to pre-check the functionality of the automated voice annunciator system. The system could be used to verify the operation and build quality of other electronic onboard systems on new buses as they come off the assembly line, allowing in-plant inspectors to make more informed evaluations before accepting buses. Preven- tive measures taken at the plant have the potential to save the manufacturer money by addressing quality issues before buses arrive at the agency. CENTRAL NEW YORK REGIONAL TRANSPORTATION AUTHORITY Introduction Centro operates 279 buses under 32 different classifications, which collectively fit into 19 different PM schedules. This case study examines how the agency manages its PM program given the diversity. Agency Background Centro is headquartered in Syracuse, New York, and serves the counties of Onondaga, Oneida, Cayuga, and Oswego. The agency has a staff of 675 employees; its fleet travels 7,500,000 miles annually carrying approximately 38,000 pas- sengers daily and 14.4 million passengers annually. Bus Classifications Despite having 279 buses under 32 different classifications, Centro separates them into two basic categories for the pur- poses of conducting PM: 1. Full-size transit buses (30 ft and larger), of which the agency has a total of 229; and 2. Paratransit buses, of which it has a total of 50. Of the 229 full-size buses, 102 are traditional diesel, 120 are powered by CNG, and 9 are hybrids. Table 16 shows the full- size bus fleet and Table 17 shows the paratransit fleet. Both tables also include the respective class designation code for each bus type. The codes are important because they are used to assign buses to specific PM inspections. Preventive Maintenance Classifications As mentioned previously, Centro has PM classifications for full-size buses and another for the smaller paratransit fleet. Table 18 shows the various PM schedules established for
36 its full-size bus fleet. The intervals are based on a base 6,000 mile âAâ PM, where an entire vehicle inspection takes place along with an engine oil and filter change. The âBâ inspection takes place every 12,000 miles, and consists of an âAâ inspection with the addition of replacing the fuel filter and cleaning the centrifugal filter. Centroâs âB2â inspection, which takes place every 36,000 or 72,000 miles depending on the bus, consists of repeating the âAâ and âBâ services with the addition of replacing the transmission fluid and filter. All mileage-based PM intervals also have a time- based alternative. For example, the âAâ PM takes place every 6,000 miles or six months, whichever comes first. The remaining inspections are time-based (i.e., every 45 days, etc.). Centro has separate PM inspections for the electrical system; the HVAC system; wheelchair lifts; fire suppression system; farebox; air drier; and a PM inspection that encompasses the driverâs seat, destination signs, and the emergency windows. There are also separate time-based inter- vals for engine tune-ups and chassis dynamometer testing. PM schedules for Centroâs paratransit bus fleet consists of only two inspection categories. As with the larger buses, the base âAâ inspection is set at 6,000 miles and includes an engine oil and filter change. The âBâ inspection, which takes place every 18,000 miles, repeats the âAâ inspection and adds transmission fluid and filter replacements. Table 19 shows the two inspection classifications for Centroâs paratransit buses. Although the oil change interval for buses powered by International engines is 14,000 miles, the interval was changed to 6,000 miles because of excessive bus idling as revealed by oil analysis. The agency is firmly committed to its oil analy- sis program, which includes both engine oil and transmission fluid. Identifying solids and other contaminates in the oil/fluid allows Centro to take maintenance and repair action before a relatively minor problem results in catastrophic failure. Preventive Maintenance Procedures Each department within Centroâs maintenance organization is responsible for conducting its own PM inspections. Elec- trical, HVAC, farebox, and other dedicated departments within maintenance have their own specialized inspection Bus Type Bus Class Designation Code Quantity 2007 GilligâHybrid 07HB 9 2003 35 Ft Orion VâCNG 2003 5 30 Ft New Flyer D30LFâDiesel 3004 10 1999 Orion VâDiesel 3099 6 2007 Gillig 35 FtâDiesel 3507 2 2008 Gillig 40 FtâDiesel 3608 3 2008 Gillig 30 FtâDiesel 3708 3 40 Ft New Flyer D40LFâDiesel 40D05 23 40 Ft New Flyer C40LFâCNG 40G05 8 40 Ft New Flyer C40LFâCNG 40H05 11 1991 40 Ft Orion V DSLâDiesel 500 1 1999 40 Ft Orion VâCNG 599 78 1995, 96, 00 MCI 102D3âDiesel 601 12 1996 Orion VâDiesel 960RI 4 1997 Nova BusâCNG 97N5 18 1999 Orion VâDiesel 990RI 22 2009 Gillig 35 ftâDiesel 3709 4 2009 Gillig 40 ftâDiesel 3609 5 2009 MCI D4000âDiesel 901 5 TABLE 16 CENTRO FULL-SIZE BUS FLEET Bus Type 2003 Ford Van 2006 Eldorado Aerotech 2003/04 Ford Van 2005 Ford Van 2007 Ford Van 2009 Eldorado Aeroelite 2009 Ameritrans Bus Class Designation Code 03FOH 2006P 203 205 207 209 0209 Quantity 3 3 15 8 4 13 4 TABLE 17 CENTRO PARATRANSIT BUS FLEET
37 Designation Activity Interval Bus Class Designation Codes A PM Service PM inspection Oil/filter change 6,000 mi/6 mos. 501, 599, 600, 601, 2003, 97N5, 3004, 40DO5, 40G05, 40H05, 07HB, 96ORI 990RI, 3608, 3708, 3609, 3709, 901 B PM Service A PM service Fuel filter Centrifugal oil filter 12,000 mi/12 mos. 501, 599, 600, 601, 2003, 97N5, 3004, 40DO5, 40G05, 40H05, 07HB, 96ORI, 990RI, 3608, 3708, 3609, 3709, 901 B2 PM Service A PM service B PM service Transmission fluid and filter change (synthetic) 72,000 mi/96 mos. 501, 599, 601, 6010, 2003, 3004, 40DO5, 40G05, 40H05, 07HB, 96ORI, 990RI, 3608, 3708, 3609, 3709, 901 B2 PM Service A PM service B PM service Transmission fluid and filter change (synthetic) Water filter 36,000 mi/24 mos. 97N5 C1 PM Service A PM service B PM service Transmission fluid and filter change (synthetic) One time only at 3,000 mi Newly purchased vehicles only D Inspection Chassis dynamometer testing Every 365 days All E Inspection Complete electrical system inspection Every 365 days All F Inspection Complete fire suppression system inspection Every 180 days 599, 97N5, 2003, 3004, 40DO5, 40G05, 40H05, 07HB, 3507, 3608, 3708, 3609, 3709, 901 F2 Inspection Replace fire suppression squib Every two years 599, 97N5, 2003, 3004 (older buses are equipped with a manual style actuator that is required to be replaced at a 2-year interval) F6 Inspection Replace fire suppression chemical agent tank Every six years 599, 97N5, 2003, 3004, 40DO5, 40G05, 40H05, 7HB, 3507, 3608, 3708, 3709, 901 (new buses are equipped with an electronic actuator that last 12 years, but are changed at the 6-year interval) G Inspection Complete farebox inspection Every 90 days All with farebox TABLE 18 PM CLASSIFICATIONS FOR FULL-SIZE BUSES (Continued on next page)
38 H Inspection Complete HVAC inspection Every 180 days All H1 Inspection HVAC filter replacement Every 45 days 07HB L Inspection Complete wheelchair lift inspection Every 45 days All with lift and ramps N Inspection PM cartridge (with oil separator) Every 365 days All N2 PM air drier Every 2 years All Q Inspection PM driver seat, PM destination signs Every 180 days All T Inspection CNG tank inspection Every three years All with CNG TU Inspection Engine tune-up Every 365 days All Designation Activity Interval Bus Class Designation Codes TABLE 18 (continued) Designation Activity Interval Bus Class Designation Codes A PM Service PM inspection Oil/filter change Wheelchair lift inspection 6,000 mi/6 mos. 201, 203, 205, 207, 209, 0209, 03FOH, 2006P B PM Service A PM service Transmission fluid and filter change Fuel filter Air filter 18,000 mi 201, 203, 205, 207, 209, 0209, 03FOH, 2006P F Inspection Complete fire suppression system inspection Every 180 days 209, 0209 F6 Inspection Replace fire suppression chemical agent tank Every six years 209, 0209 N2 PM air drier Every two years 209, 0209 TABLE 19 PM CLASSIFICATIONS FOR PARATRANSIT BUSES
39 crews responsible for conducting PM activities. Within each department one work crew is dedicated to inspections, whereas another is dedicated to repairing defects found during inspec- tions. Safety-related defects are repaired immediately, whereas other defects noted during inspections are rescheduled for a later time. Centro uses the Jakware Fleet Management System to track PM activities. The system schedules the appropriate PM inspection based on the bus mileage and its designation code. For example, 1994 40-ft Orion V diesel buses have a designa- tion code of 501. The MIS schedules buses with that designa- tion code to receive PM services according to the following schedule: ⢠âAâ PM (oil and filter change) every 6,000 miles or six months, ⢠âBâ PM (fuel and centrifugal oil filter) every 12,000 miles or 12 months, ⢠âB2â PM (transmission) every 36,000 miles or 24 months 97N5 RTS Novaâs only, ⢠âB-2â PM (transmission) every 72,000 miles or 96 months, ⢠âC-1â PM one-time inspection at 3,000-mile interval, ⢠âDâ PM (chassis dynamometer) every year, ⢠âEâ PM (electrical) every year, ⢠âFâ PM (fire suppression) every 180 days, ⢠âF2â PM (squib replacement) every 2 years, ⢠âF6â PM Chemical agent tank replacement every 6 years, ⢠âGâ PM (farebox) every 90 days, ⢠âHâ PM HVAC inspection every 180 days, ⢠âH1â PM HVAC filter replacement hybrid buses only, ⢠âLâ PM (wheelchair lift) every 45 days, ⢠âNâ air drier cartridge w/oil separator every 1 year, ⢠âN2â air drier âFâ PM (fire suppression) every 180 days, ⢠âQâ PM (driver seat, destination sign, emergency windows) every 180 days, ⢠âTâ PM CNG tank inspection every 3 years, and ⢠âTUâ PM (engine tune up) every year. Buses with other designation codes receive PM services according to other schedules depending on the bus type and its onboard equipment. Every work order generated for a PM inspection has its own unique checklist tailored to a specific bus type or com- ponent. In addition to âchecking offâ that a specific item was inspected, checklists also require technicians to record certain information such as brake adjustment measurements and mea- suring stopping distance measurements during brake tests. Technicians performing the inspections, as well as those repairing noted defects, are trained by Centro before being required to perform their duties. Most of the training involves working with a first-class mechanic and monitoring perfor- mance to ensure they are qualified to handle the assigned PM tasks. The agency strives to make all repairs noted as part of the PM inspection that same day, depending on parts availabil- ity and scheduling. The MIS generates a separate work order for every defect identified during the PM inspection. Work orders remain âopenâ (unresolved) until a repair is made to correct the specified defect, whereby the work order is then âclosedâ (resolved). If multiple work orders are open on the same bus, the technician is required to indicate separately whether they will also be making those repairs. If not, they must indicate the reason for keeping the work orders open. The agency has a policy of closing out all work orders at the end of each month. Specialized Preventive Maintenance Activities Centro has specialized PM classifications to address specific bus equipment such as the electrical system, HVAC system, and the fire suppression system. The agency has also devel- oped special procedures for its CNG and hybrid bus fleets. The intent of these specialized PM activities is to focus atten- tion on certain bus areas and repair any noted defects as part of a scheduled activity to minimize unscheduled work. Electrical Preventive Maintenance The âEâ electrical PM inspection takes place annually on all full-size buses. It was initiated three years ago to address the many electrical-related defects typically found during âAâ inspections, and because of road calls and service interrup- tions caused by these defects. Since instituting the âEâ inspec- tions on an annual basis, service interruptions for electrical problems have been significantly reduced. The six-page âEâ inspection addresses all electrical areas of the bus, including electrically controlled aspects of the air system. It includes 28 different electrical areas such as the starting and charging systems, lights, multiplex system, inter- locks, accelerator and brake pedals, public address (PA) sys- tem, kneeling system, wheelchair lift, electrically controlled brake valves, and all other electrical/electronic areas of the bus. Incorporating brake system inspections into the âEâ inspection works well because so much of the braking sys- tem, including the anti-lock braking system, is electrically controlled, and because at Centro the electrical and pneu- matic departments are combined. Heating Ventilation and Air Conditioning Preventive Maintenance The HVAC or âHâ inspection takes place on each bus every six months to check the entire system. There is one inspec- tion protocol for buses with air conditioning, and another for those without it. Inspections are classified by bus area, denot- ing certain tasks for equipment located on the street side of the bus, in the engine compartment, the defroster compartment,
and other such areas. A separate âH1â inspection, which takes on certain buses every 45 days, replaces a series of HVAC- related air filters. Fire Suppression Preventive Maintenance The fire suppression or âFâ inspection is based in part on OEM specifications, as well as requirements set forth by the National Fire Protection Association. There are 23 separate procedures for conducting this inspection with detailed work instructions provided that they also include a series of warn- ings and notes. For example, one warning reminds techni- cians to always install a shipping plate and an anti-recoil plate when transporting a pressurized agent cylinder. A note included in the inspection procedures reminds technicians to avoid using solvents when cleaning gauge faces to prevent damaging the plastic face. Instructions are very detailed and use a step-by-step process. Centroâs separate âF2â PM inspection replaces the fire suppression squib every two years, whereas the âF6â inspec- tion replaces the chemical agent tank every six years. Hybrid Preventive Maintenance To address the PM needs of its hybrid buses, Centro uses its existing PM schedule developed for similar diesel buses with the addition of unique PM tasks for hybrids. For example, according to the OEM, battery cooling filters unique to Cen- troâs hybrid buses require replacement every 15 days. How- ever, after evaluation, the agency determined that filters were not sufficiently dirty after this interval and extended the inter- val to 45 days to coincide with its âH1â HVAC inspection when cabin filters are replaced. For hybrid buses, Centroâs âH1â inspection also includes a battery cooling filter replace- ment. Centro, however, continues to evaluate the replacement of this filter and is considering extending its replacement beyond 45 days. At the âB2â inspection, where transmission fluid is changed every 72,000 miles on traditional buses, Centro replaces fluids and filters unique to the hybrid drive unit, which on the Allison system replaces the traditional transmission. The synthetic fluid used in the hybrid unit is identical to that of the standard transmission, and so is the fluid change interval. For 40 Centro, as with every agency, new PM requirements that can be kept within the framework of existing PM intervals avoid the downtime associated with creating separate intervals. Centro is closely monitoring fluid quality through its oil analysis program. As a result of the findings, the agency has reduced the interval (i.e., made it more frequent) for some transmissions and may do the same for its hybrid fleet. Compressed Natural Gas Preventive Maintenance Centroâs CNG buses adhere to the same PM schedule as diesel buses, but with added procedures. Because CNG buses have a spark ignition system, tune-ups for these engines consist of changing sparkplugs and CNG tanks and piping is inspected for leaks as part of the âTâ inspection. Although the OEM suggests changing the crankcase breathers at 18,000-mile intervals, Centro changes them at 6,000 miles because con- densation buildup clogs the filter and will freeze in the win- ter resulting in elevated crankcase pressure. Centro uses the same 6,000-mile interval for its diesel buses equipped with crankcase ventilation filters. Other Agency Initiated Preventive Maintenance Activities Based on its experiences and operating environment, Centro has also initiated other PM activities: ⢠Fuel filters are replaced every 12,000 miles to avoid problems such as freezing in the winter. ⢠Air cleaners are changed every 18,000 miles because salt used on roadways in the winter shows up in the oil analysis results as high sodium and magnesium in the crankcase. Also, when the ambient air humidity is high and there is salt on the road, it actually draws the salt in through the air cleaner. ⢠During the âLâ (wheelchair lift) inspection the hydraulic filter is replaced every 45 days even though the OEM suggests an annual replacement. ⢠An âNâ inspection was recently added to replace the air drier cartridge annually. ⢠Engines and radiators are steam cleaned within 90 days to mitigate overheating problems, especially those caused by clogged radiators.
