More weight, more problems
The issues with SEPTA’s Proterra buses started before they had ever picked up paying passengers.
Back in 2017, SEPTA selected two pilot routes to demo the new Proterras. Both were in South Philadelphia and specifically chosen because they were short and flat — optimal conditions for buses that need regular recharging and with battery life that dwindled over hilly terrain. But even those routes needed buses to pull around 100 miles each day, while the Proterras were averaging just 30 to 50 miles per charge. Officials also quickly realized there wasn’t room at the ends of either route for charging stations.
Eventually, SEPTA issued a change order asking Proterra to supply longer-range buses to ease the recharging churn — essentially, vehicles loaded with more batteries that could average closer to 100 miles a day before recharging. The agency further poured millions into upgrading the nearby Southern Bus Depot to provide space for charging stations.
By the time the buses were delivered in 2019, SEPTA’s PR campaign around the introduction of the new, greener buses was in full swing. Becky Collins, SEPTA’s corporate initiatives manager for sustainability, depicted the agency as having overcome the aforementioned logistical hurdles with Proterra’s cutting edge fleet of long-range buses.
“The technology keeps on improving,” Collins said of the new fleet in a June 2019 Inquirer article about the bus launch. “It just keeps on getting better and better and better.”
But by that point, both SEPTA and Proterra already knew the heavier buses were cracking.
A letter from Proterra to SEPTA states that “non-structural skin coat cracks” were first detected in bus chassis in May 2019, a month before they began formal service. But the hairline cracks were dismissed by the company as purely cosmetic, and SEPTA spokesperson Andrew Busch said Proterra developed a plan to repair the cracks by fall of that year, promising it “would not reoccur.”
The cracking issue, of course, did recur. In some instances, atop prior repairs. Photographs circulated internally show cracks were everywhere on some buses — around windows, doorways, light fixtures — sometimes with thumb-size pieces of chassis missing.
SEPTA mechanics also discovered yet another issue in January 2020: The brackets holding roof-mounted equipment were failing. The manufacturer agreed to repair the brackets but continued to insist the cracks were “a non-structural, cosmetic issue.”
SEPTA didn’t buy it this time. The buses were taken out of service in February 2020.
“This continuation of the cracking issue raised concerns by SEPTA that the root cause of the cracking was not identified or corrected by Proterra, and that these cracks could be, or could propagate into, structural issues,” Busch said.
What followed was a protracted legal back-and-forth that continues today, with Proterra maintaining the buses should be put back into service and SEPTA insisting on a fix.
“Proterra and its structural consultant … have been uncooperative in the resolution process,” wrote chief vehicle engineering officer Dave Warner last summer.
The official cause of the issues remains a point of debate because of this ongoing dispute. But some sources believed the switch to heavier, long-range buses needed for even SEPTA’s shorter routes could be the culprit.
Ofsevit said the underlying problem is that batteries are simply far heavier than a fossil-fuel tank and yet provide less energy output — leading manufacturers to add more hefty batteries while cutting frame weight to compensate.
“Battery electric buses have used composite frames to pull down the weight,” he said. “But that can have unintended consequences when you’re shifting the mass, adding additional batteries. You’re moving more weight to the front or back axles.”
Proterra frames were made out of a composite material. Unlike all-metal frames, they used a mix of resin, fiberglass, carbon fiber, balsa wood, and steel reinforcement plates, according to a SEPTA report on the cracks. Company lawyers would later analogize the issue to cracking paint applied to a metal frame, raising doubts the issue could ever be “fixed.”
“Proterra is unable to repair or permanently prevent the recurrence of … cracking because it is an inherent part of the composite body material,” wrote Josh Ensign, Proterra’s chief operating officer.
Still, today, Proterra maintains that SEPTA’s fleet will be put back into service — eventually.
“We are working cooperatively and productively with SEPTA to put their buses back in service so that riders and the community can realize the benefits of our clean, quiet, zero-emission electric transit buses,” wrote company spokesperson Shane Levy. “Our buses have provided over 20 million service miles to communities across North America, and we look forward to our buses serving the needs of SEPTA transit riders.”
But in the meantime, there have been other costs related to the issues. SEPTA retained Duane Morris attorneys to assist in the Proterra dispute as outside counsel, billing the agency for over $57,000 as of June 2021. Energy provider PECO had bought out a two-year $650,000 bus ad contract to promote the all-electric fleet SEPTA, which ended after the Proterras were taken out of service. (Busch said the timing was incidental, and that the contract had simply run its course).
Internal SEPTA emails show that as the bus issues crept into a second year, some seemed to be growing frustrated there would ever be a resolution.
“In regards to the Proterra buses, we are still hopeful that their buses will eventually be back in service? Truly?” wrote assistant general manager Kim Scott Heinle in February 2021.