Automatic Equipment Identification (AEI) Tags

Automatic Equipment Identification (AEI) tags are passive RFID transponder tags mounted on rail cars and locomotives so that equipment can be identified automatically as it moves. They are the electronic identification component of a piece of rolling stock.

Where They Sit

An AEI tag is mounted on each side of every car and locomotive, low on the body so it lines up with trackside readers. The tags are passive, meaning they carry no battery; they draw the power to respond from the radio signal of the reader as the car passes. Fixed AEI readers are installed alongside the track at yards, interchange points, and along the line.

What They Do

Each tag is encoded with the car's identity, principally its reporting marks and car number, the same identification stenciled on the side of the car. As a car rolls past a trackside reader, the reader energizes the tag and reads back that stored identity, recording which car passed and when. This lets railroads track the location and movement of equipment automatically, without a person having to read and write down each car number, and supports car accounting, train consist verification, and interchange records.

Inspection

For the system to work, the tags must be present, correctly programmed with the car's current marks and number, and readable. A missing, damaged, or mis-programmed tag breaks automatic tracking of that car. AEI tag requirements and programming follow AAR standards so that any reader on the network can identify any car.