Cedar Point's Magnum XL-200 is almost fully loaded.
The roller coaster was shut down and two trains removed last month after a train loaded with people bumped into the back of another train sitting on the tracks outside the loading station. Three people were slightly injured from the incident.
The two trains sustained minor fiberglass damage and were removed for inspection and repair work.
One of the trains has now been replaced, and the ride is now operating with two trains, said park spokesman Bryan Edwards.
"We hope to put the third one back on as soon as maintenance finishes it," he said.
Edwards said the testing procedure is the same as what the park maintenance department does during the off season.