Winter was hard in Scotland this year, not least during February 23–25 when Terex Construction had invited 160 customers and dealers from emerging markets to Motherwell. So the company’s white and anthracite TA300 articulated dump truck (ADT) made its first appearance in a cold white and gray setting—familiar weather for the several Russian customers in the group that E&MJ joined, less so for those from the Middle East. The larger TA400, launched previously, was also put through its paces.

Terex said its Motherwell team started the design process for the latest generation of trucks with a thorough competitor analysis and “voice of the customer” consultations. Following rigorous prototype testing in challenging conditions around the world, Terex believes that the TA300 and TA400 are the ultimate ADTs: powerful, quick, tough, reliable and easy to maintain.

Six-wheel Smoothness
Competing in the major 30-ton size class for construction, road maintenance, small mining and quarrying ADTs, the TA300 is designed to give both the owner and the operator the features they want: safe high performance, low cost maintenance and comfort that allows the operator to work optimally through the shift.

Specifically, the TA300 weighs 22,485 kg (49,573 lb) net, offers a 28,000-kg (30.9-ton) payload and a 17.5-m3 (22.9-yd3) heaped capacity, among the largest in class. The body dump cycle time is 20 seconds. The weight distribution is 11,753 kg (25,913 lb) on the front axle, 5,315 kg (11,718 lb) on the leading bogie axle and 5,417 kg (11,942 lb) on the trailing bogie axle. Fitted with 23.5 R25 tires, the unloaded truck exerts a ground pressure of 119 kPa (17.2 psi) at the front and 541 kPa (78 psi) at the rear. Loaded, the pressures rise to 170 kPa (24.6 psi) at the front and rear. Body options include liner plates and side extensions.

The standard power unit is a Tier 3 compliant Cummins QSM 11 six-cylinder engine delivering 287 kW (385 hp) gross power, which Terex says is the highest power and torque in this truck class. CANbus electronic control technology keeps the engine at peak efficiency at all times. Top speed is 50.4 km/h (31.3 mph). The heavy duty countershaft transmission is the 6WG 310 RPC from ZF which is fully automatic with manual override and linked to a Transmission Visual Display Unit. The axles are from the German manufacturer NAF (Neunkirchen Achsenfabrik AG) which Terex has worked with since April 2006. There are inter-axle and cross-axle differential locks providing 100% locking action. Load-sensing hydraulics reduce power loss, fuel consumption and heat generation, while the high-capacity cooling system enables the TA300 to operate across the climate range from Arctic to hot desert.

In addition to the wet disc braking system there is a two-stage automatic or manual engine braking system for hauling safely downhill without using the service brakes, which increases productivity and reduces operator fatigue, said Terex. However, perhaps the feature of the latest Terex trucks that differentiates them most from competitors is the cutting- edge, double-wishbone independent front suspension. The use of IFS began with the TA300’s predecessor, the TA30, but the system has been improved to provide an even better and quicker ride on rough terrain. A reduction in truck body vibration levels also extends service life, Terex added. The bogie beam rear suspension allows independent wheel movement to further improve the truck’s ride characteristics

Elevated Operator Comfort
Together with the independent front suspension, the state-of-the-art ROPS/FOPS cab provides comfortable accommodation through the shift, with air suspension seat, new tilt/telescopic steering wheel, reduced in-cab noise levels and better sound system, air conditioning that has been upgraded to provide better temperature control and updated interior aesthetics with a matte finish to reduce glare. Operator effectiveness is increased by the excellent visibility, sun visor, tinted glass, four rear view mirrors and reversing safety camera/monitor system, and by arrangement of well-sized controls in logical groups on either side of the steering wheel

Minimized Downtime
The systems most susceptible to wear and tear have been designed to perform through long service intervals, maximizing uptime, and to be as easy and quick to service as possible, minimizing downtime. The oil-cooled, multiple wet disc brake system is a case in point. As well as being more efficient overall than traditional dry disc brake systems used on standard competing ADTs, said Terex, the fully enclosed system on the TA300 provides longer service intervals. Service brake life is further increased by using the Jacobs compression-release engine brake for retardation. The rear bogie is 100% maintenance-free. Ground level service access points and the tilting cab also make significant contributions to service time reduction.

Comparing the TA300 with major competing trucks, George McNeil, Terex’s global product manager for articulated trucks, claimed some significant advantages, noting that gross torque is higher and the service brakes are better than those on the Volvo A30E, which also does not have a Jacobs engine brake. McNeil also stated the TA300 has a higher capacity and better power-to-weight ratio than the Komatsu HM300. Similarly it has more engine power and lower net vehicle weight than the Caterpillar 730, which also lacks oil-cooled disc brakes. And the TA300 has better rimpull and higher capacity than the Bell B30D. Although these differences help the Bell to achieve lower fuel consumption than the Terex, the TA300 is slightly better on this measure than the Volvo and significantly better than the Cat and Komatsu machines according to customer data, he added.

The TA400: High Speed, Heavy Duty
According to McNeil, the TA400 is the most durable and productive ADT that Terex has ever produced. Capacity is 38 mt (41.9 ton) and 23.3 m3 (30.3 yd3), making this truck well suited to small mining applications. With a Tier 3 compliant, fuel efficient 336-kW (450-hp) Detroit Diesel Series 60 engine delivering a maximum torque of 1,350 Nm (1,548 ft-lb) at 2,100 rpm through a fully automatic or manual Allison HD4560 planetary transmission and high/low ratio drop box, the truck has a top speed of 60 km/h (37.3 mph), the highest in this size class. Rimpull and gradeability are also high.

Globally, about 30% of the 30- and 40-ton class ADTs are sold to mining, with 70% for construction applications— although in South Africa the split is 50:50 or perhaps more than 50% in mining use. Since the launch of the Terex Generation 7 ADTs in 2002 the company has put 4,332 machines into the field, McNeil estimates. Although global ADT sales were generally very depressed in 2009 there were bright spots, notably South Africa and Indonesia, while stocks of both new and used machines have been reduced, so the launch of the machine at this time, planned some years back, may be better timed than it might first appear.