PORTLAND, Ore. (KOIN) — Commuters might need to plan on taking an earlier MAX train than usual in the intense heat Tuesday.

This week, TriMet says it is slowing down trains to keep the system safe while it battles temperatures expected to remain above 90 degrees for multiple days.

Sometimes, rails expand and bend when it’s hot enough, transit officials say, which leads to further delays.

The MAX Green and Orange lines are delayed when it’s above 90, but every line is affected above 100 degrees.

TriMet says riders can expect to add about 20 minutes to their trips when the line is slowed. Riders can check delays here.