This mobile crane has been modified for railroad track maintenance. The crane is positioned over the tracks, then guide wheels are lowered so the machine follows the railroad tracks as it moves forward or backward. These guide wheels also add stability to the machine. The initial machine design used all hydraulic controls to move the boom. This configuration added significant complexity to the machine since hydraulic lines had to be routed into the cab while the cab can rotate 360 degrees. Further, on-off hydraulic controls resulted in less precise boom movement, greater opportunity for operator error, and forced the operator to manually control the engine rpm so that adequate hydraulic power would be available.
GS Global Resources (GSGR) significantly improved machine performance, safety, and reduced fuel consumption by implementing a total machine control system. Electronic joysticks provide a proportional output to hydraulic valves so that boom movements are smooth and precise. An electronic foot pedal is an important part of the control system to allow smooth acceleration and deceleration of the crane as it moves along the railroad track. The master controller integrates all of the control devices, monitors and controls the engine rpm, and provides proportional control to all of the electro-hydraulic valves. Application-specific CAN software coordinates all of these elements into a single total machine control system. As a result, the machine operates in a smooth, precise manner, machine attachments are easily interchanged, productivity is improved, costly and cumbersome hydraulic hoses and rotational devices have been eliminated from the cab.