The hybrid buses evaluated were part of an order of 125 Orion VII hybrid buses with the BAE Systems series hybrid propulsion system. The buses started service in March 2004 at Mother Clara Hale Depot in Manhattan and later were also introduced at Queens Village Depot in Queens. This group of buses is the first large commercial hybrid bus delivery for Orion and BAE Systems. NYCT expected the 125 hybrid buses to seamlessly replace diesel buses after special training for high power and troubleshooting and battery conditioning activities were completed.
The CNG evaluation presented in this report includes 10 CNG Orion VII buses (model year 2002) chosen at random at West Farms Depot and nine diesel Orion V buses (model year 1994) used as a depot baseline. The baseline fleet for this evaluation is nearing the end of its useful life at NYCT (11 out of 12 years of planned use). The newer CNG buses have generally replaced the diesel buses at the depot with higher usage and lower operating costs. While comparison of newer technology to older diesel buses is not optimal, having a baseline is still valuable to fleets considering these advanced buses. In many cases, the buses being replaced are similar to those of NYCT: near or past their planned life.
The hybrid evaluation presented in this report includes 10 hybrid Orion VII buses (model year
chosen at random at Mother Clara Hale Depot and nine diesel Orion V buses (model year
used as a depot baseline. Although the bus model years differ by only three years, because
the hybrid buses did not go into service until 2004, the diesel buses are five years older in terms of operations experience. The newer hybrid buses have generally replaced the diesel bus fleet at the depot with similar usage and much higher fuel economy and better fuel cost per mile performance.
One note of context for this evaluation: The DDC Series 50 engine is no longer available for new transit buses. Both the diesel and CNG engines are no longer available.
The evaluation presented in this report includes comparisons of CNG and hybrid Orion VII buses to older diesel buses at the two depots for bus usage, fuel economy, and miles between roadcalls (MBRC). Because of the age difference of the diesel buses and the CNG and hybrid buses (as well as warranty costs), the maintenance cost per mile comparisons are only accomplished between the CNG and hybrid Orion VII buses. The comparison of the Orion VII CNG and hybrid buses includes buses that are the same age and the same bus platform. The CNG buses at West Farms Depot and the hybrid buses at Mother Clara Hale Depot have been operated on similar duty-cycles and the maintenance practices at the two depots appear to be similar.
The implementation experience of the CNG (260 buses) and hybrid (125 buses) fleets went well, and the buses were quickly put into full service. NYCT, Orion, and BAE Systems reported that the buses are performing well from a systems perspective. West Farms Depot built a large CNG compression station that has the ability to move 6,600 scfm of natural gas and fuel buses in less than 5 minutes. Combustible gas detection was added for the maintenance area to accommodate the use of natural gas buses. The hybrid buses required that adequate space be available at the Mother Clara Hale facility for two battery conditioning stations.