Регуляторы выявили трещины в редукторах нового подвижного состава BART, несмотря на заверения перевозчика об отсутствии угрозы безопасности

Cracks have been found on the gearboxes of dozens of BART’s Fleet of the Future train cars – sometimes after only one year in service – according to a new analysis ordered by state regulators and obtained by NBC Bay Area’s Investigative Unit under the state’s Public Records Act. Both BART and the train maker, Alstom, stress that while cracks have been found on the top covers of the new fleet gearboxes, they are not a safety concern. They say a redesigned, crack-resistant gearbox top cover is now undergoing testing. Watch NBC Bay Area News free wherever you are But one expert says any cracks must be considered a red flag, given the vital function of the gearbox. “The gearbox is a high-performance system,” said Don Mullen, a former BART engineer who worked on its legacy fleet. Mullen says that the gearbox functions the same as a transmission in a car, serving to automatically control the spinning of train axles and wheels. He said the old fleet shared the same gearbox design, but its gearbox was rarely a problem. Maintenance logs reviewed by NBC Bay Area’s Investigative Unit indicate leaks of gearbox lubricant have been found along with cracking. Any unchecked leak could potentially compromise the gearbox’s critical speed-control function, Mullen says, and should be considered a major concern. “Leaking oil out of a gear case, analogous to a transmission in your car, is not a good thing,” Mullen said, calling on more tests to assure that the gearbox integrity is not being compromised in the new fleet. The Investigative Unit Have a tip for The Investigative Unit? Call 1-888-996-TIPS. “It can't be ignored,” Mullen stressed. The study that identified the cracking issue was performed by a third-party consultant. Records obtained by NBC Bay Area show it was launched at the order of the state’s Public Utilities Commission back in 2022. Regulators intervened after an anonymous insider pointed to concerns raised by BART’s own engineers about safety impacts to the gearbox of a glitch that has long plagued the new fleet -- sudden braking during wet weather. In slippery conditions, BART says, new fleet car sensors kick on, activating emergency brakes on all cars at once. The sudden braking grinds flat spots that force entire trains in to have wheels resurfaced. At a cost of $8,000 per car, according to BART documents. BART engineers complained to the trainmaker about the flat problem, documents show. They also indicate engineers warned about the potential damage to the gearbox over time due to all the sudden braking. BART cited the sudden wet-weather braking issue as one of the reasons it stopped accepting new train cars from Alstom back in 2021. But a year later, BART resumed shipments, telling regulators that slowing speeds in wet weather should resolve the issue. But in 2022, the insider contacted rail regulators with the CPUC, pointing them to the concerns previously raised by BART’s own engineers over the potential risk to the gearbox from repeated sudden braking, according to CPUC documents. BART documents show its engineers told Alstom at the time that the risk to the gearbox from stresses from sudden braking over the long term must be considered a potential Level One concern, until proven otherwise. A Level One concern is defined as one that poses “an immediate safety or reliability risk.” To address delays associated with the braking, BART spent $4 million last year to reprogram trains to slow down automatically in braking-related trouble spots. However, BART maintenance records reviewed by NBC Bay Area show dozens of cars still needed to have their wheels resurfaced last winter because of sudden braking. The cost is currently being borne under the warranty. The gearbox risk study, which relies on computer analysis, noted that cracks have formed on a “large number” of gearbox covers due to “high stress and insufficient fatigue safety factors.” The housing of the gearbox met safety margins, the report found, but the cover material did not meet minimum fatigue safety standards. The cracking failures began showing up, the study found, after trains were in service for a year. The report concluded the “likely cause of the cover crack failures” was stress, both from braking in service and the stress inflected by tightening down the covers during installation. In a statement, BART confirmed that so far, more than 200 covers have been replaced on the new fleet. But didn’t specify whether all of them were cracked. It did acknowledge gearbox cracks can cause “minor oil weeping” that’s addressed in service. BART did not address the findings of the gearbox analysis in detail, however, saying only: “BART does not consider this a safety issue.” Alstom said in a statement that it conducted “a comprehensive analysis” and determined the gearbox cover issue “has no impact on safety or performance of the trains,” and added it has enhanced the cover design “to address the cracking.” But Mullen says the only way to know whether the new fleet’s gearboxes are, in fact, safe is to do field tests under the extreme forces of sudden braking, rather than rely solely on computer modeling to rule out the risk of a catastrophic failure, like a derailment. “You need to be conservative,’’ Mullen said. “The public's trusting you. They bought the system. They paid for it with their tax money. They use it and assume it always works.” State regulators say BART has told them it expects field testing to be done next year.