It's interesting to note that one of the reasons Cat began upgrading its excavators to D-series configuration was to make the machines easier to operate with less skilled labor. With the recent, sharp increases in fuel and consumables costs eating away at the quarrying and mining industry's potential profits, equipment owners are becoming increasingly aware of the direct and indirect costs of careless, improper or inefficient machine operation. And they are looking more closely at simulator training, which can teach or reinforce proper operating techniques without taking a machine out of production or risking damage while being used for training. Two relatively low-cost PC-based simulator products for excavators have been recently introduced.

Caterpillar's Equipment Training Solutions Group has developed a PC-based Virtual Training System for hydraulic excavators that can be used as a self-study tool or as part of a program led by an instructor. The system is designed to advance students through increasingly difficult modules to enable the trainee to build skills. The trainee receives instant feedback to show where improvement is needed. Examples of feedback include time to perform task, accuracy of task and undesirable actions during the task. The trainee's skills level can be measured, reported and compared to performance criteria so that competency weaknesses are quickly identified.

The system uses a lightweight, portable seat and console unit equipped with excavator joystick controls and foot pedals. The computer-generated graphics can be displayed on an optional large-screen monitor for added realism.

Vista Training offers a simulator training program that is explained in detail in the new product section on page 41.

John Deere has brought out a line of D-series excavators. The company says these units have faster hydraulics, a redesigned cab, undercarriage enhancements and a new cooling system. The cabs have an adjustable suspension seat and added legroom. There is 47% more right-hand window glass and a larger roof-hatch area. There are shorter pilot controls, and generous hydraulic flow and metering provide powerful digging force, precise control and multi-function operation. A multi-function monitor has gauges, warning lights, and icons for operating information in multiple languages. Screens provide access to warning messages, attachment preferences, and maintenance and service information. The company says the hydraulic system boosts productivity by up to 8%.

The 240D LC and 350D LC feature PowerTech engines. The 450D LC, 650D LC and 850D LC use Isuzu engines. All of these engines are Tier-3 compliant and employ a four-valve design with cooled-exhaust gas recirculation that reduces oxygen. An electronically controlled variable-geometry turbocharger matches engine speed to load requirements on the 240D LC, 270D LC and 350D LC models. These three models also have improved fuel efficiency. The hydraulically driven cool-on-demand fan runs only as needed, reducing noise, fuel consumption and operating costs. The 350D LC undercarriage has larger upper and lower rollers, strong idlers, and thicker links. Service intervals have been extended to 5,000 hours on the hydraulic system. Remote-mount oil and fuel filters are located in the pump compartments, so they can be changed without crawling under the machine or removing access panels. Daily service points are grouped and accessible through a large service door.

The D-series operating weight ranges from 54,244 pounds for the 240D to 106,180 pounds for the 450D to 185,520 pounds for the 850D. Draw pull for those machines range from 49,920 pounds, to 79,590 pounds, to 126,194 pounds, respectively. Bucket force on those machines, respectively, is 37,670, 57,111, and 80,703 pounds.