State safety inspector Jerold Miller observed in the report that three drive belts were missing from the top drive motor and one belt was missing from the bottom drive motor during (the) examination. Whether the belts were absent at the time of the incident or whether the incident caused them to come off the pulley is unknown.
The injuries would have resulted from an over-normal operating speed condition brought on by the large passenger volume and the missing motor drive belts.
This item concludes the first page of Miller’s handwritten notes: Belts were off drive!
As people were leaving a Beyonc performance on July 15, shortly after midnight, the incident occurred at the Vine City station. People were thrown into a lump on the platform at the base of the moving stairs when the escalator abruptly stopped after speeding up.
Despite citing a high passenger traffic as a contributing factor, the report does not state that the number of people using the stairs surpassed the 8,000-pound working capacity. Additionally, as several experts have previously told the AJC, it doesn’t seem to address whether the braking system ought to have applied as the escalator started to tumble downward.
MARTA’s claim that there was no mechanical issue with the escalator appears to be refuted by the report. Officials from the transit agency claimed that a stampede on the escalator was the root of the problems. But that explanation seems to be contested by victims, witnesses, and security camera evidence.
Citing possible legal action, MARTA representatives chose not to comment on the report.
On July 16, the day following the incident, Miller met with MARTA representatives and mechanics from maintenance contractor Schindler. Miller noted in the report that when removing two escalator steps for inspection, he discovered that the top drive motor pulley was missing all three drive belts.
We then looked at the bottom drive motor; according to the report, two belts had walked to the top side of the pulleys, and one belt was off the pulley.
Credit: Georgia Fire Commissioner’s Office of Insurance and Safety
Credit: Georgia Fire Commissioner’s Office of Insurance and Safety
According to Tony Boom, an electrical expert with more than 30 years of experience working with escalators, if the belts had broken loose while the escalator was operating, the stairs might have accelerated quickly. In a prior AJC piece, Boom was one of three experts who stated that brake failure was most likely the cause of the collision. The state’s probe does not involve him.
Boom, who examined the state report and accompanying records at the AJC’s request, stated that if all drive motor belts had been absent prior to the incident, the escalator would not have been functional. He claimed that the overspeed should have been recognized and stopped by the escalator’s safety system.
Boom stated that he continues to think that the braking problem is ultimately to blame.
Boom stated that when the escalator started to travel too quickly, the brakes should have applied in a tenth of a second, or roughly 100 milliseconds. Whatever caused the initial fault, the fact that they didn’t and the escalator plunged downward for just over seven seconds suggests a braking problem, he added.
Whether or not the brake should have activated is not discussed in the state report. The agency has been contacted by the AJC for clarification.
In any case, Boom claimed that the number of people on the escalator in the security tape indicates that it was not overcrowded, at least not to the point where it began to speed without stopping.
He claimed that there was another issue. The over-speed was due to something else.
Even though the majority of people were off the escalator, it was still moving too fast when you looked at the top of it. Why, therefore, is it still going on, going really fast, while the majority of people are away? That indicates to me that the brake is not applied.
According to work logs supplied by MARTA, the escalator was installed in 2011 and had just completed standard maintenance on July 10—days before it crashed.
The standard monthly things were ticked off, along with annual, semiannual, and quarterly maintenance duties. One of the things examined was brake capacity.
The state report states that while the Vine City escalator is being fixed, it will stay out of service.
