Steel braces were replaced on the SkyTrain bridge spanning the Fraser River between New Westminster and Surrey on Friday evening after engineers found cracks in them.
Several engineers found the cracks in so-called "stiffeners" in the steel box carrying the rails on the north end of the bridge, near Columbia Station, during a routine inspection.
The cracks are not a safety hazard, engineers said, but part of the normal wear and tear on the system.
SkyTrain service was slowed down temporarily but was operating normally by Saturday morning, according to TransLink spokesperson Ken Hardie.