TriMet says a relatively new part called a surge arrestor failed Monday morning, disrupting MAX service throughout the region for hours.
Service did not resume until mere hours before the start of the Portland Trail Blazer and Portland Winterhawks games in the Rose Garden, which many fans use MAX to reach.
According to TriMet, "The system of transformers and lines that brings electricity to the MAX system is extraordinarily complex. There are dozens of possible points of failure, and many potential errors that can cause an uneven power flow. In today's system of electricity distribution, power surges are an unavoidable occurrence. The surge arrestor is the mechanism that is designed to control these occurrences and we have numerous arrestors throughout the system."
TriMet says surge arrestors normally last 15 to 20 years. The agency recently replaced those 20 or more years old. The one that failed was among those replaced.