VTA restores hybrid bus batteries in-house for maintenance efficiency

California's Santa Clara Valley Transportation Authority (VTA) is finding new, more efficient ways to maintain its fleet of buses and trains at the highest standards of service, according to the agency.

Close to a quarter of VTA’s bus fleet are Allison hybrid/diesel buses, which run on a combination of an electric motor and a diesel engine. This provides a more environmentally friendly output of emissions than traditional diesel engines. Electric-drive systems have fewer mechanical parts, which require less maintenance than traditional transmissions.

These 90 buses were purchased almost nine years ago and, as they approach mid-life, some components are approaching the end of their expected optimum-service life.

Here’s where VTA is on the leading edge of equipment maintenance. Most transit agency mechanics do routine mechanical work but hire outside specialty mechanics to completely overhaul or replace major components such as transmissions, hybrid/diesel and standard diesel engines and Hybrid Energy Storage System (ESS). VTA mechanics are doing the highly skilled work of restoring the batteries, or “energy storage systems” (ESS), as they’re called, all in-house.

VTA mechanics have been doing something similar with light rail cars that are required to be overhauled after travelling a certain number of miles. The Kinkisharyo light rail cars require complex work to rebuild, with a limited number of experienced experts in the U.S. to do the work. VTA mechanics have the training and expertise to do the work in house, according to the agency.

VTA can keep costs low by rebuilding the hybrid/diesel engines and refreshing the hybrid batteries using locally sourced and more affordable Prius batteries and its own mechanics. The transit agency is taking a conservative approach to the project. By maintaining readiness of the buses through early resourcing, training and quarterly scheduled rebuilds, we ensure staff remains proficient and supplies and funding are available. As the batteries begin to degrade to 70% of their original capacity or show increased signs of degradation, we can kick the rebuild schedule into high gear.  

Work on these batteries has already begun, and the entire fleet of hybrid/diesel will have their batteries restored as the need arises.