According to useful life standards provided by the Federal Transit Administration (FTA), the fleet is considered large, heavy-duty transit buses with a maximum useful life of 12 years or 500,000 miles.

Currently the bus fleet averages six years in age (median age is 10 years old) and 230,000 miles in use. Of the seven (7) buses in the fleet, the four Nabi/Bluebird buses have required 12 combined engine rebuilds and two of those buses have required four engine rebuilds. Each engine rebuild lasts an average of 100,000 miles before failure and costs about $28,000 to complete. This trend is anticipated to continue for the remaining life span of these units.

In comparison to FTA useful life standards for the fleet type, (12 years and 500,000 miles), the fleet is in line with useful life standards, as GVRTA vehicles average at least 40,000 miles of use per year. FTA considers 41,700 miles per year proper usage based on a 12 year/500,000 useful life designation.

Unfortunately, while the age and mileage of the four Nabi/Bluebird buses would indicate a “fair” condition assessment at this stage of life, the three buses in service now are rated in “marginal” condition.
This is primarily due to the service conditions the buses are used for. Using the buses at highway speeds in extreme winter weather conditions has caused premature failure of the following major components.

  • As discussed above, engines. Engines are replaced at 100,000 mile intervals and last approximately 2.5 years. Cost to replace an engine is currently $28,000.
  • Fuel injectors on the buses are replaced at roughly 80,000 -100,000 mile intervals. Most diesel engines require injector replacement at 100,000 – 200,000 miles. Cost to replace injectors is approximately $5,000-$6,000 per bus.
  • Multiple turbo charger failure, with a cost of $2,000 each.
  • Lift maintenance time and expense has been significant. The lifts are prone to collecting road grime, magnesium chloride, and dust due to their location. It has been extremely difficult to procure ordered parts from the ADA lift manufacturer in a timely fashion.
  • Electrical wiring of the buses has also been extremely problematic. The manufacturer has never been able to provide accurate schematics for each bus. Some fuse box locations are not marked on wiring diagrams. Actual wire color used varies from bus to bus for the same systems. In the event of an electrical fault, the contractor often “reverse engineers” the affected system in order to repair it. As a result, there is a steep learning curve required for electrical troubleshooting that has added to maintenance costs and downtime.

In should be noted that Nabi/Bluebird parts are increasing difficult to locate in a timely manner or have been discontinued. While lights, windshields, switches, and most base electronic parts are easy to come by, parts such as power steering pumps, fan drive pumps/solenoids, windshield wiper motors, ADA cassette parts, radiators, and interior panels/bezels are very difficult, if not impossible to acquire.

*Vehicle years, mileage, engine hours, and condition ratings provided in APPENDIX A.