Washington State Ferries officials said the ferry system is taking new steps to prevent the engine meltdown suffered by the ferry M/V Walla Walla during ferry work at the Eagle Harbor Maintenance Facility from happening again.

The announcement came at the close of an investigation that determined that work by WSF employees at the Bainbridge yard was the cause of an engine failure aboard the Walla Walla that resulted in a repair bill of $3 million.

WSF said it would establish and follow checklists and associated written procedures for infrequent and complex maintenance work, and mandate pre-work meetings prior to work being performed on vital equipment with all associated personnel.

Workers will also be trained before infrequent and complex maintenance jobs are started. The shipyard will also reinforce established lock out/tag out procedures.

The 188-car ferry Walla Walla was knocked out of service Nov. 4 after an electric drive motor failed while the ferry was undergoing routine annual maintenance at WSF’s Eagle Harbor Maintenance Facility on Bainbridge Island.

WSF announced the results of a three-month probe into the meltdown on March 11. The investigation was finished Feb. 25.

Investigators said the damage could have been avoidable and resulted from mistakes made by Washington State Ferries personnel.

The ferry system launched an internal safety investigation after the incident, and also hired the Cadick Corporation, an electrical power system engineering firm, to help in the investigation as a third-party expert.

“We conducted a thorough and detailed investigation into what happened and why,” said David Moseley, assistant secretary of the ferries division of the Washington State Department of Transportation.

“Safety is our number-one priority at WSF. We need to learn from these mistakes and focus on improving complex maintenance practices,” he said.

The Walla Walla is expected to return to service in April.

The damage occurred during scheduled work on an electric drive motor on the Walla Walla, one of four propulsion motors aboard the vessel.

Ferry officials said the procedure required WSF vessel engineers and maintenance staff to engage an electrical current to power two of the motors in separate motor rooms located at each end of the vessel.

According to the final investigation report, crews improperly set electrical circuits to prevent the current from reaching an inactive motor in an unstaffed motor room. The current melted vital parts of the inactive motor over a period of 40 minutes.

WSF said investigators concluded that two separate crews each assumed the other had taken proper steps to safely contain the electrical current, and said the crews’ lack of familiarity with the system’s circuitry and reliance on inadequate institutional knowledge were contributing factors.

WSF has been working with the drive motor manufacturer to refurbish WSF’s only spare motor for jumbo-class ferries to get the Walla Walla back into service.

The ferry will undergo extensive testing and sea trials after the refurbished motor is installed.