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Massachusetts Bay Transportation Authority History of Preventative Maintenance and Best Practices on Disc Brakes
History of the MBTA
• The MBTA can look back on a tradition of hundreds years of continuous mass transportation services.
• From the earliest beginnings to the present, the MBTA can be proud of its long tradition of innovation and progress.
• While claiming to be America's oldest subway, it still remains the vibrant life stream of Boston and Eastern Massachusetts.
• The MBTA remains the nation's 5th largest mass transit system.
• It serves a population of 4,817,014 (2010 census) in 176 cities and towns with an area of 3,249 square miles.
• To carry out its mission it maintains 183 bus routes, 2 of which are Bus Rapid Transit lines, 3 rapid transit lines, 5 light rail (Central Subway/Green Line) routes, 4 trackless trolley lines and 13 commuter rail routes.
• Its roster of equipment consists of :
• 922 diesel and CNG buses, 25 hybrid parallel drive, 60 diesel/electric hybrid drive, 32 dual mode buses, 28 ETB′s (electric trolley buses),
• 410 heavy rail vehicles, 200 light rail vehicles, 10 PCC's streetcars,
• 90 commuter rail locomotives, 410 commuter rail coaches
• and 464 MBTA-owned specially equipped vans and sedans, and an additional 182 contractor-supplied specially equipped vans and sedans.
• The average weekday ridership for the entire system is approximately 1.3 million passenger trips.
History of the MBTA
History of the MBTA
MBTA Fleet of Buses 1042 Total
• 878 – Conventional (Diesel or CNG) 40ft Buses MY1994 to 2008
• 60 - Hybrid BAE (Diesel/Electric) 40ft Buses MY2014
• 44 – CNG 60ft Articulating Buses MY2003
• 25 – Hybrid (Allison Parallel Drive) 60ft Articulating buses MY2010
• 32 – Dual Mode/Skoda Drive 60ft Articulating Buses MY2004
• 28 – Trackless Trolley (Electric) 40ft Buses MY2004
Current Fleet of Buses
Current Fleet of Buses
MBTA Fleet of Buses with Disc Brakes 164 15.7% of Total MBTA Fleet
Current Fleet of Buses with Disc Brakes
• 44 – CNG 60ft Articulating Buses• 32 – Dual Mode/Skoda Drive 60ft Articulating Buses• 28 – Trackless Trolley (Electric) 40ft Buses• 60- Hybrid BAE (Diesel/Electric) 40ft Buses
• Allison B500R (with Retarder)
• Front Axle – ZF RL-85/A with Knorr SB7000 Disc Brakes
• Center Axle – ZF AVN132 with Knorr SB7000 Disc Brakes
• Rear Axle – M.A.N. HP-1352-B with 16 1/8” S-cam Brakes
• GVW 67,700lbs
• DDC Series 60 Gas engine
Current Fleet of Buses with Disc Brakes44 -2003 Neoplan 60’ Articulating Bus QM-Series CNG
• Average Life to Date Mileage is 250,000 miles plus
• Average Front Axle Brake Pad Life – 40 to 50,000 miles
• Average Center Axle Brake Pad Life – 12,000 miles
FSRP: Addressed Plumbing to Center Axle & Type 24/24 to 20/24 Brake Chambers (to improve miles between replacement)
• Average 3X Brake Pads to Caliper & Rotor Replacement
Current Fleet of Buses with Disc Brakes44 -2003 Neoplan 60’ Articulating Bus QM-Series CNG
Current Fleet of Buses with Disc Brakes32 - 2004 Neoplan 60’ Articulating Bus RA-Series DMA
• DDC Series – 60 500hp Generator
• Skoda (2X) 420 3-Phase Traction Motor (with Regenerative Braking)
• Front Axle – ZF RL-85/A with Knorr SB7000 Disc Brakes
• Center Axle – ZF AV/132 with Knorr SB7000 Disc Brakes
• Rear Axle – ZF AV/132 with Knorr SB7000 Disc Brakes
• GVW 64,700lbs
Current Fleet of Buses with Disc Brakes32 - 2004 Neoplan 60’ Articulating Bus RA-Series DMA
• Average Life to Date Mileage is 250,000 miles plus
• Average Front, Center & Rear Axle Brake Pad Life –100,000miles plus
• Replacement usually due to corrosion or failure not exceeding wear limits
Current Fleet of Buses with Disc Brakes28 - 2004 Neoplan 40’ QN - Series ETB
• Skoda Propulsion (with Regenerative Braking)
• Front Axle – ZF RL-85/A with Knorr SB7000 Disc Brakes
• Rear Axle – ZF AV/132 with Knorr SB7000 Disc Brakes
• GVW 43,640lbs
Current Fleet of Buses with Disc Brakes28 - 2004 Neoplan 40’ QN - Series ETB
• Average Life to Date Mileage is 220,000 miles
• Average Front, Center & Rear Axle Brake Pad Life –100,000miles plus
• Replacement usually due to corrosion or failure not exceeding wear limits
Current Fleet of Buses with Disc Brakes60 - 2014 New Flyer 40’ Xcelsior SR1881/1902 Hybrid Bus
• Cummins ISB 6.7L
• BAE Hybrid Drive System (with Regenerative Braking)
• Front Axle – M.A.N. VOK-07-F Knorr SN7000 Disc Brakes
• Rear Axle – M.A.N. HY-1350-F Knorr SN7000 Disc Brakes
• GVW 43,640lbs
Current Fleet of Buses with Disc Brakes60 - 2014 New Flyer 40’ Xcelsior SR1881/1902 Hybrid Bus
• Average Life to Date Mileage is 50,000 miles plus
• No Disc Brake Issues To Date
Bus Maintenance Training
MBTA Bus OperationsMaintenance Training Phase 1 - PMI
Preventative Maintenance Inspections:Each candidate must:•Master all preventative maintenance inspection procedures and complete these procedures in a timely manner.•Demonstrate ability to complete minor repairs during inspection process.•Master the proper nomenclature for all parts identified during an inspection.•Pass the final exam within the allotted six month time frame, Failure to do so will result in termination from the program.•32 hours classroom / 120 hours hand on vehicle preventive maintenance training after which the candidate will be assigned to their facility for the remainder of the 6 month phase. •The candidate will be given a written and hands on test at the conclusion of the phase
Preventative Maintenance Inspections:
Each candidate must:
• Master all preventative maintenance inspection procedures and complete these procedures in a timely manner.
• Demonstrate ability to complete minor repairs during inspection process.
• Master the proper nomenclature for all parts identified during an inspection.
• Pass the final exam within the allotted six month time frame. Failure to do so will result in termination from the program.
• 32 hours classroom / 120 hours hand on vehicle preventive maintenance training after which the candidate will be assigned to their facility for the remainder of the 6 month phase.
• The candidate will be given a written and hands on test at the conclusion of the phase
MBTA Bus OperationsMaintenance Training Phase 1 - PMI
MBTA Bus OperationsMaintenance Training
Phase 2 – Brakes and Suspensions
Brakes; Steering; Suspension
Each candidate must:
•Master the basic air system.
•Master the brake rebuild standard procedure.
•Wedge brake; S-Cam Brakes; MAN planetary gear axles; Meritor; Rockwell and Knorr disc brakes
•Master the antilock braking system (Wabco ABS).
• Demonstrate the ability to complete undercarriage component change outs. (i.e. radius rods, bellows, shock absorbers etc.)
• Pass the final exam within the allotted six months time frame. Failure to do so will result in termination from the program.
• 8 hours classroom / 72 hours hand on vehicle brakes; steering and suspension training after which the candidate will be assigned to their facility for the remainder of the 6 month phase.
• The candidate will be given a written and hands on test at the conclusion of this phase.
Phase 2 - Brakes and SuspensionsMBTA Bus OperationsMaintenance Training
MBTA Bus OperationsMaintenance Training Phase 3 – Electrical
Electrical:
Each candidate must:
• Demonstrate the ability to follow basic troubleshooting procedures.
• Basic Electrical; Multiplexing; Starting Circuits; Generators and Charging; Destination signs; Door control; ADA systems; Camera Systems; Auxiliary heaters; Heating, ventilation and air conditioning.
• Must pass the EPA Section 609 Certification Exam
• Either pass this phase in the allotted six-month time frame or repeat the phase. A candidate who does not pass the phase during the second six-month period will be terminated from the program.
• 32 hours classroom / 120 hours hand on vehicle preventive maintenance training after which the candidate will be assigned to their facility for the remainder of the 6 month phase.
Phase 3 – ElectricalPhase 3 – ElectricalMBTA Bus OperationsMaintenance Training
MBTA Bus OperationsMaintenance Training Phase 3 – Electrical
Electrical: (cont.)
Each candidate must:
•The candidate will be given a written and hands on test at the conclusion of the phase
• 160 hours classroom and hands on vehicle electrical diagnostics and repair procedures after which the candidate will be assigned to their facility for the remainder of the 6 month phase.
•The candidate will be given a written and hands on test at the conclusion of the phase
Phase 3 – ElectricalPhase 3 – ElectricalMBTA Bus OperationsMaintenance Training
MBTA Bus OperationsMaintenance Training Phase 4 – Power Train
Power Train:
Each candidate must:
• Master standard tune-up procedures.
• Demonstrate the ability to follow standard troubleshooting procedures for engines and transmissions.
• Perform major engine component change-outs in a timely manner.
• Cummins; Detroit Diesel; Caterpillar
• Perform transmission removals and replacements in a timely manner.
• Allison WTEC/ATEC; V731;WTEC II/III/Gen4
Phase 4 – Power TrainMBTA Bus OperationsMaintenance Training
MBTA Bus OperationsMaintenance Training Phase 4 – Power Train
Power Train: (cont.)
Each candidate must:
• Either pass this phase in the allotted six-month time frame or repeat the phase. A candidate who does not pass the phase during the second six-month period will be terminated from the program.
• 40 hours classroom and 200 hours hands on vehicle power train diagnostic, tune up and repair procedures after which the candidate will be assigned to their facility for the remainder of the 6 month phase.
• The candidate will be given a written and hands on test at the conclusion of the phase
Phase 4 – Power TrainMBTA Bus OperationsMaintenance Training
Preventative Maintenance
MBTA performs preventive maintenance inspections PMI’s based on mileage at 6,000 mile intervals recommended by the OEM’s.
We have 6, 12, 18, 24 thru 72,000 mile inspection forms and then revert back to 6,000 mile inspection and start over again.
6K Preventative MaintenanceInspection Line Items
3. Road Test/Drive bus with “Brake Regeneration Switch” = OFF (to clean brake rotor surfaces) Return switch to the ON position afterward.
32. Brake calipers should move back and forth freely on the brake pins. Inspect brake lining wear with brakes released from rubber boot wear indicator.
Hold for reline. Check Type: Front _____ Rear _____SPB for reline. Check Type: Front _____ Rear _____
33. Inspect brake chambers and air lines for leaks; securements; routing; damage.
34. Inspect ABS sensor and modulation valves connectors/wiring for securements; routing; damage front and rear.
32. Brake calipers should move back and forth freely on the brake pins. Inspect brake lining wear with brakes released from rubber boot wear indicator.
Hold for reline. Check Type: Front ________ Rear _________SPB for reline. Check Type: Front ________ Rear _________
33. Inspect brake chambers and air lines for leaks; securements; routing; damage.
34. Inspect ABS sensor and modulation valves connectors/wiring for securements; routing; damage front and rear.
3. Road Test/Drive bus with “Brake Regeneration Switch” = OFF (to clean brake rotor surfaces) Return switch to the ON position afterward.
*NOTE: All wheels need to be removed for brake inspection
36K Preventative MaintenanceInspection Line Items
Best PracticePreventive Maintenance Inspections
• Attention during inspections to brake caliper seals, boots and protective cap during inspections to prevent brake caliper failures
• Contamination of the internal mechanism of the caliper is the leading cause of brake caliper failures).
• Road Test/Drive bus with “Brake Regeneration Switch” = OFF (to clean brake rotor surfaces) Return switch to the ON position afterward.
Preventive maintenance of air system
• Moisture and contaminates
• Leading cause of dragging brake
• Brake interlock /hill hold solenoid, relay valves etc.
Yearly /36K-Inspection
• Disc brake “wheel off” inspection or whenever a wheel is removed
ConclusionFleet of Buses with Disc Brakes (15.7%) are currently at 3 of 9 garages
Location #1
CNG 60ft Articulating Buses & Dual Mode/Skoda Drive 60ft Articulating Buses
• Two classifications (machinist / repairers) maintaining two different fleets one location)
• Both fleets have different duty cycles and applications
(1 fleet with regenerative braking)
• 1st Approach of repairs was to replace seals / boots & pins at location
• 2nd Approach of repairs is to replace the caliper with a rebuilt / remanufactured or new caliper.
Conclusion
Location #2
28 Trackless Trolley (Electric) 40ft Buses
• Rebuilds brake calipers in-house.
• Regenerative braking.
Conclusion• Location #3 Hybrid BAE (Diesel/Electric) 40ft Buses
• 50,000miles plus with no brake work to date.
• All 3-locations with disc brakes experience:
•Less down time with brake repairs.
• Less driver complaints of “poor brakes” or “brakes pulling to the right or left”
Conclusion• All 3-locations with disc brakes experience:
•Less down time with brake repairs.
• Less driver complaints of “poor brakes” or “brakes pulling to the right or left”
