PORTLAND, Ore. (KOIN) — In September, TriMet launched its new, bendy FX buses designed for faster travel and more riders. Nearly two months later, service on the new buses has been halted due to a mechanical issue.

The alert that TriMet sent out on Wednesday, Nov. 2, says, “Standard 40-foot buses will temporarily serve FX2-Division stations out of an abundance of caution due to a fleet-wide mechanical issue. We are working with the manufacturer, Nova Bus, to address the issue and return the articulated buses to service as soon as possible.”

Before being removed, the FX buses traveled along a 15-mile route from downtown Portland to Gresham with arrivals every 12 minutes. They were also equipped with bike racks on board, saving cyclists the hassle of hanging up their bikes on the front of the bus. Additionally, the 60-foot buses could hold 60% more riders than the standard TriMet buses.

A statement issued by TriMet Director of Communications Roberta Altstadt on Monday detailed that the mechanical issue was detected on inspection rather than during travel.

“…an operator noticed a noise when turning one of the articulated buses. A mechanic then investigated and found that a fastener or bolt that connects a mounting plate to the frame of a bus was missing,” Altstadt said.

According to the statement, further inspection conducted by TriMet maintenance staff revealed that four of the six inspected buses had loose fasteners. The other two’s fasteners were completely missing.

TriMet removed the new buses “out of an abundance of caution.” The standard buses serving the FX2-division line are operating on the same schedule, but without the all-door boarding and bike racks on board.

The TriMet Operations team is paying close attention to rider loads, and more buses will be added if necessary.

“Just as it’s disappointing to have an issue or recall on a brand new car that needs to be addressed, we feel the same about our brand new FX articulated buses, but we will keep them off the road until the issue is corrected,” Altstadt said. “We appreciate the diligence of the operator who reported the odd noise and our maintenance team for identifying the issue and immediately removing the buses from service. The safety of our riders, operators and the communities we serve is not just important, it is what we at TriMet value.”

FX bus manufacturer Nova Bus is currently working to identify what caused the mechanical issue.