Several updates to the controls have also improved the MAX-TRAC traction/ABS control system and the MAX-TRAN hydraulic lift system. When the first Titan was designed with the Cummins Tier 3 electronic control engines in 2006, the decision was made to use CAN bus technology throughout the new product line. With goals of increasing operator comfort, safety and performance, we researched many CAN systems and settled on Class 1, which designs and produces custom electronic instrumentation, controls, and plumbing components for heavy duty-ground vehicles.

 

In the old system, engine and braking systems were controlled with pneumatic foot pedals. The hydraulic coupler lift and traverse cylinders were operated by switches on the console. Pneumatic rail wheel sanding switches were mounted in the corners of the cab, and an air horn was actuated by pulling a chain in the ceiling. In other words, the controls were everywhere!

To streamline this, a joystick mounted on the right armrest of an air-cushioned seat now controls the throttle and brakes. The joystick head also contains switches for transmission control, air horn, pneumatic coupler release, and sanding for traction. The left side of the seat has a small control panel that operates the front and rear hydraulic couplers. Also on this panel is a four-position joystick. This electronically controls the rail car’s air brakes. Everything needed to operate the Trackmobile is within easy reach — 22 items are operated from the seat controls and only four wires exit the seat, 12 V positive, negative, plus CAN Hi and CAN Low.

The two CAN wires transmit the commands from the seat module to other modules in the Trackmobile. These modules then send a voltage signal to the hydraulic and pneumatic valves and also the engine throttle. Braking is controlled by wire using a custom module built by Class 1 that controls an electronic MICO brake valve.

The instrument panel was redesigned using a digital display. All the engine, transmission and vehicle parameters are displayed here. This feature greatly simplifies the panel compared to previous models, which had a variety of mechanical gauges.

Bob Evans, engineering manager at Trackmobile, Inc., LaGrange, Ga., can be reached at bobevans@trackmobile.com or (706) 884-6651 ext 236. Learn more at www.trackmobile.com.

Click here to see a video of the Trackmobile's Viking in action.
 

Hydraulics, pneumatics provide system-wide power and control

Pioneering a unique air compressor design
Trackmobile pioneered the first high volume, rotary screw air compressor to be driven from a transmission’s power takeoff. Working with Ingersoll Rand’s engineers, a proprietary splined shaft was designed for Trackmobile’s compressors. The rotary screw compressor’s duty cycle can be operated 100% of the time, as opposed to only about 20% for a reciprocating compressor. This is useful in mobile rail car movers while charging the train air brakes on cars for long periods of time.

Remote control improves data collection
Trackmobiles have been remote controlled for decades. Earlier this year, we started using Scanreco Remote Control Systems (www.scanreco.com). The CAN Bus receiver on board the unit controls the same functions that are in the seat control but information on the CAN bus— fuel level, hydraulic temperature, air compressor temperature, transmission, engine data, and rail car air brake pressure — can be sent back to the transmitter.

Hydraulic fan drive meets TIER 4 needs
Trackmobile is now into the TIER 4 engines, which require much higher cooling capacities. Instead of engine driven cooling fans for the larger radiators, Trackmobile went with a hydraulic driven fan. The existing hydraulic system pump that operates the coupler functions also operates the engine cooling fan. The control for the fan uses the CAN Bus system to communicate engine, transmission, and hydraulic parameters and determines how much flow to direct to the fan motor. The belt driven fan system was obviously engine speed dependent. The hydraulically driven fan can operate at full speed while the engine is at idle, which helps reduce the size of the radiator. If cooling is not needed, the fan will operate at slower speeds, thus conserving horsepower and reducing noise.

Trackmobiles are operated in various environments from very clean (rare) to extremely dirty (the norm), such as paper mills and plastics industries. Wood chips and plastic pellets in these rail yards will eventually plug the radiator of a belt driven fan. The hydraulic fan system on the TIER 4 Trackmobile will, after a period of time, ramp down the speed to 0 rpm and ramp back up in the opposite direction for a short period. This prevents overheating by keeping the radiator from building up debris because the reverse air flow blows debris clear.