The Railroad's Electronic Detectives
Out on the track can be found some unusual detection devices which provide our railroad a large amount of security. To be sure, the improvement in design of railcars over the years has dramatically reduced the problems which these devices watch for, such as the “hotbox” or burnt off axle journal, but at the same time there has come a reduction in the number of people who could provide the same kind of security. There are three particular devices in use, each of which detects a particular bad condition and notifies the train dispatcher or the train crew so that appropriate action can be taken before a mishap occurs.
The Hot Box Detector senses an excessive amount of heat in any journal of a railcar as it passes the device. The temperature of the bearing is an indication of the lubrication conditions (a high temperature indicates lubrication failure, suggesting a breakdown of the bearing). When a high reading is obtained, the potential for the axle to fail warrants fast action. These devices send out an automated radio alert message directly to the train crew, or a graph of the journal temperature for each axle in a train is transmitted to the dispatcher’s office which allows the dispatcher to decide the action to be taken.
The successes of the hot box detectors in preventing damage to the railroad have justified a continuing program of installing additional detectors. Improvements in design have reduced the first cost as well as refining the indication to provide more accurate results. Derailments have always been the major consequence of hotboxes, and these devices have proven to be effective in preventing such derailments.
The Dragging Equipment Detector is another of the devices which act to protect the movement of trains. This device is activated when contacted by anything, since it occupies the space adjacent to the rails into which no part of any locomotive or car should normally protrude.
A derailed wheel or a fallen piece of brake rigging would be the usual culprit and these, of course, are potential causes of big problems, especially if the car is dislodged from the track. Car design improvement has greatly reduced the possibility of brake rigging problems, and the attention paid to equipment and track maintenance reduces the chance of the derailed wheel. Still, the protection afforded is of great value.
The High Car Detector is the third device which checks the train consist. This device utilizes an electric eye to sense of any car in a consist is excessively high and capable of striking any object in the route, such as a bridge. As cars and containers have become progressively higher as clearances have been increased, the high car detector is also used to verify the nature of a consist in order to allow routing to be determined.
These “detectives” are in use on Guilford Rail System in varying locations and in different combinations. Typical examples are portrayed in the photographs. Design improvements are ongoing, and yet the oldest devices continue to provide a valuable service in protecting the operation. New detectors, which incorporate both the hot journal and dragging equipment detection functions, are planned for installation at Gray and Readfield, Maine, in 1999.
