UPDATE: Light rail service slowly restored througout the region after morning rush hour disruptions.

As if the commuting nightmare in the Portland region couldn't get any worse, a MAX train derailed in the Rose Quarter early Friday.

Although crews were able to get it back on the tracks by around 8 a.m., Jan. 13, light-rail service was disrupted in much of the region. TriMet officials urged riders to use buses instead of MAX trains, even though some bus routes are canceled because of the snow, while others on snow routes are delayed.

No one was injured in the incident, which occured at about 4:50 a.m. TriMet was able to restore service between Portland and Gesham by around 6 a.m. Service was slowly restored throughout the day.

TriMet spokeswoman Roberta Altstadt, speaking on KPAM radio at 7:30 a.m., said the situation was unique for the MAX line: Ice had never built up enough to force a train off the tracks before today. It's unknown if the train or the wheels were damaged, she said, although crews were working on the problem as she spoke.

According to TriMet, MAX service was originally disrupted between Old Town/Chinatown and Gateway Transit Center, as well as along the entire Orange/Yellow Line. At the height of the disruption, MAX trains are only running on the:

Blue Line between Hillsboro and Goose Hollow;

Blue Line between Gresham and the Gateway Transit Center; Red Line between Gateway Transit Center and Portland International Airport; and the Green Line between Gateway Transit Center and Clackamas Town Center.

TriMet says the derailment took place when an early morning train was moving from the Blue Line alignment to the Yellow Line alignment. After stopping at the Rose Quarter Transit Center, the train was moving slowly through a little-used section of track to reach the Yellow Line at Interstate/Rose Quarter. Ice had built up in the track, causing the train to slide off the rails. The track section is only used in the late night and early morning hours.

Check trimet.org/#alerts for updates.