TrackSide Detectors Trackside Detectors are usually spaced every 10-20 miles and at some hazard spots like the bottom of hills and at the ends of yards. They are embedded underneath the track and scan every axle of the train for any hotspots emmiting from hot brake bads or locked wheels. These can be very dangerous on a train as it jeapordizes the brake system or can start fires. Not only do they protect the train, they can inform railfans where a train is located on the line and for railfans on the train, just how fast they really are going. Detectors can pickup hotboxes, dragging equipment and high/wide equipment.

To see the only High and Wide detector in this area drive along Balls Ferry Rd. past Cottonwood going towards the Coleman Fish Hatchery. The road will first be parallel on the north side just outside Cottonwood and then do an "S" (crossing the tracks) and end up on the south side until Panorama Pt. Before you hit that crossing look on the track to your right and you will see a pole that goes over the tracks. The pole, along with the supports on the sides have sensors hanging from the top and protruding from the sides testing for rocking/shifted equipment or too high of equipment. This detector was placed for northbound trains to stop at Redding and unload (setout) their DoubleStack Cars because they couldn't go through the Mt. Shasta area tunnels and such. For the southbound trains, it detected doublestack cars at first and wide cars for the upcoming bridge over Cottonwood Crk. Hwy 5 at the time was too low for the doublestack cars going over the creek but now Hwy 5 was raised and expanded both for railroad right of way and earthquake safety.
Now the doublestacks will go through the detector with no problem southbound and northbound and will detect higher than normal and of course too-wide of a sway or shifted load. I believe the doublestacks can now transverse through the Cascades but I am not sure yet. (A train just tripped a high detector now on the scanner! Strange hehehe) I will get a picture of this detector soon hopefully

A detector is automatic and very easy to hear over the ROAD channel of the line. Usually a female voice as (this is true!) the women's voice is very attention grabbing. And it is easy to hear in any conditions of noise and interference. When the first engine hits the box, the box will announce its presence, alerting the engineer that pertinent info will come soon after the train goes over the box. After the last car passes over the box it starts transmitting the information in the following format...
"UP Detector, milepost xxx.x
xx miles per hour
no defects, no defects
Axle count xxx
Ambient Temperature (optional)
Detector Out"

If a detector finds a defect then it's a different story! And you will not miss it! :)
Here is the normal script for a detector warning.....with an alarm sound ringing in the background.
"Detector, milepost xxx.x, xx miles per hour
Stop the train, stop the train
Hotbox detected, stop the train, hotbox detected
Axle count from front (#of axles from the front of the train and on which side)
Axle count from rear (#of axles from the rear of the train and on which side)"

What train does if defect is found
When a train hits the detector and it announces a defect the train must follow certain rules pertaining to the type of defect. When the detector announces the axle count of the defect, the crew member must physically count the axles from the front of the train to the indicated axle. If no problem is found at the axle, an inspection 20 axles front and back of the indicated axle on both sides must be performed.
The crew must stop the train and inspect the whole train both sides when a malfunctioning detector indicates a defect or if a message is not understood.
To test for hotboxes and hotwheels, a device called a tempilstik is applied to certain spots of the wheel and axle. The tempilstik will melt if it is too hot.
If the detector is malfunctioning and does not give a defect warning, the train must reduce to 35mph or less to the next detector. They must stay at this speed unless a roll-by inspection is performed (no less than 10mph while inspector visually checks the train) or it passes the next detector with all clear. A detector is considered inoperative when a malfunction message is sent without a defect message or no verbal indicator is given after clearing the detector.