RailRoadFan.com

With the ongoing track work on the Mt Clemens Sub, CN is now working at the switch to the Turkey Trail on the north side of 8 Mile. They have dug a trench for wires for a new signal box that extends under the sidewalk on the south side of 8 Mile.

Turkey Trail Trackwork by tcamp7837, on Flickr

What are the two boxes circled in red that are on both sides of the track? It appears to be some type of detector.

CN Nolan - Trackwork by tcamp7837, on Flickr

That's an AEI tag reader.

The work CN is doing a few miles away at Milwaukee Junction is way more involved, and includes a new control point.

Amtrak has been using the Sugarhouse Wye the past couple of days to get around the work in the connection between the Holly and Shoreline Subdivision.

that is a new HBD suite

There's one of those on each side of the tracks on the NS Chicago line at milepost 445.6.
They give the milepost and "no defects." If there's a defect, they say "Critical alarm detected, contact wayside detector help desk."

Those are what railroaders call "scanners". Used to get a good line up of the train, IF they all have their AEI tags on both sides of the car. The AEI system was put in to use to help track railroad cars. Usually located at strategic location to help catch cars out of place, missing or adds. The AEI replaced the ACI multi colored reflector strips on the cars in the 70's.