A tanker found itself stuck under a Commuter Rail bridge in Somerville during the Monday morning rush hour.
There were some delays on the Lowell Line, and trains had to traverse the bridge at 5 mph, officials said.
The driver of the asphalt tanker told Metro that there were no height restriction signs on the approach to the bridge.
A spokesman for the Commuter Rail said that normal service resumed at about 10 a.m.