WRIGHT GROUP LTD. Download PDF Report
Wright Group LTD. submitted a model Streetcar RTV, Hybrid Electric, diesel-powered, 41 seat (including the driver) 61-foot bus, for a 12 yr/500,000 mile STURAA test. The odometer reading at the time of delivery was 2,428 miles. Testing started on April 14, 2009 and was completed on October 2, 2009. The Check-In section of the report provides a description of the bus and specifies its major components.
The primary part of the test program is the Structural Durability Test, which also provides the information for the Maintainability and Reliability results. The Structural Durability Test was started on May 4, 2009 and was completed on September 23, 2009.
The interior of the bus is configured with seating for 41 passengers including the driver plus 2 wheelchair positions. Free floor space will accommodate 66 standing passengers resulting in a potential load of 107 persons plus 2 wheelchair positions. At 150 lbs per person and 600 lbs per wheelchair position, this load results in a measured gross vehicle weight of 64,690 lbs. In order to avoid exceeding the GAWR (25,353 lbs) of the rear axle, ballast for 20 standing passengers was eliminated. This reduction from full capacity resulted in an adjusted measured gross vehicle weight of 62,430 lbs and was used for all dynamic testing. The middle segment was performed at a seated load weight of 55,670 lbs and the final segment was performed at a curb weight of 48,600 lbs. Durability driving resulted in unscheduled maintenance and failures that involved a variety of subsystems. A description of failures, and a complete and detailed listing of scheduled and unscheduled maintenance is provided in the Maintainability section of this report.
Accessibility, in general, was adequate, components covered in Section 1.3 (Repair and/or Replacement of Selected Subsystems) along with all other components encountered during testing, were found to be readily accessible and no restrictions were noted.
The Reliability section compiles failures that occurred during Structural Durability Testing. Breakdowns are classified according to subsystems. The data in this section are arranged so that those subsystems with more frequent problems are apparent. The problems are also listed by class as defined in Section 2. The test bus encountered no Class 1 or Class 2 failures. Of the sixty-six reported failures, fifty-one were Class 3 and nine were Class 4.
The Safety Test, (a double-lane change, obstacle avoidance test) was performed in both right-hand and left-hand directions up to a maximum test speed of 45 mph. Although tire/ground contact was maintained throughout all runs of testing, body roll and rear car fishtailing occurred during both left and right approaches at 40 and 45 mph. The performance of the bus is illustrated by a speed vs. time plot. Acceleration and gradeability test data are provided in Section 4, Performance. The average time to obtain 50 mph was 44.10 seconds.
The Shakedown Test produced a maximum final loaded deflection of 0.084 inches with a permanent set ranging between -0.005 to 0.002 inches under a distributed static load of 41,325 lbs. The Distortion Test was completed with all subsystems, doors and escape mechanisms operating properly. No water leakage was observed throughout the test. All subsystems operated properly.
The Static Towing Test was to be performed using a target load (towing force) of 58,320 lbs. Testing was terminated at approximately 45,000 lbs of force during the front 20° up pull when deformation of the manufacturer supplied towing apparatus and attaching bolts was observed. The Dynamic Towing Test was performed by means of a front-lift tow. The towing interface was accomplished using a hydraulic under-lift wrecker. The bus was towed without incident and no damage resulted from the test. The manufacturer does not recommend towing the bus from the rear, therefore, a rear test was not performed. The Jacking and Hoisting Tests were also performed without incident. The bus was found to be stable on the jack stands, and the minimum jacking clearance observed with a tire deflated was 2.7 inches.
A Fuel Economy Test was run on simulated central business district, arterial, and commuter courses. The results were 1.78 mpg, 2.23 mpg, and 3.43 mpg respectively; with an overall average of 2.21 mpg.
A series of Interior and Exterior Noise Tests was performed. These data are listed in Section 7.1 and 7.2 respectively.