Detection system keeps Metro Transit trains moving safely through Twin Cities' airport tunnel

May 24, 2022
After 20 years of service, the tunnel's alarm system was replaced this week with new equipment.

Thanks to sensors, the few people, deer and occasional raccoon that try to pass through the light-rail tunnel under the Minneapolis-St. Paul International Airport, don't often get very far without being detected.  

Sensors in the tunnel alert staff in the Metro Transit Rail Control Center that something, or someone, has entered the prohibited area. For safety reasons, trains are stopped while the tunnel is cleared by transit police.  

After 20 years of service, the tunnel's alarm system was replaced the week of May 16 with new equipment. The new system works much like the one it replaced, but with two new features – sensors that pick up movements near the underground Lindbergh Station and red flashing signals that alert operators at the tunnel entrances.  

Crews expected to finish the upgrade in January until they discovered extensive rewiring was needed. While that work stretched on, crews continued maintaining communications equipment along the Blue and Green Lines.  

"These guys were rock stars. I can’t begin to tell you how I appreciate their dedication,” said SCADA communications supervisor Jereld Hanson.  

Employees who worked on the upgrade include forepersons Mike Maghrak and Vladimir Banchik; and SCADA communications technicians Darin Rorman, Steve Eastlund, Jim Lensch, Dave Peterson, Mika Raveala and John Vooge.   

The crews should catch a break now because the new system will require less maintenance and its sensors are easier to maintain. 

"We periodically had to align the photocells to make sure they were providing the infrared beam for the security system," Hanson said. "That’s all automated now. It frees up a lot of time."