Work is well advanced on the latest expansion of the metro systems for Chile’s capital city, Santiago. The largest of the current works is the 33km long section called Line 4. It comprises sections at street level, elevated and underground. Costing US$100 million, the section is scheduled to come into service in the middle of this year. It has a design capacity of 325,000 passengers a day, and will add a further six stations to the network.
Gruas Burger, one of Chile’s largest crane rental companies, provided the cranes. The company provides cranes for a wide range of lifting operations for mining, petrochemical, forestry and industrial companies, as well as for major construction works. It specialises in heavy lifting with tailor made solutions using combinations of cranes from a fleet of 32 units of which eight units are Kobelco RK250 rough-terrain cranes.
Managing director Raul Burger says: “These cranes have been very successful because of the 30m boom plus hydraulic jib and the load chart is similar to that of larger 30 or 35t of other makes. Gruas Burger has a very strict policy towards safety, and an important feature in the Kobelco cranes is that the safety accessories such as monitoring devices, cameras and outside light (green, yellow, and red) meet our demanding standards.”
The RK250 has a lifting capacity of 25t at 3.5m. Maximum boom length is 30.6m with optional 12m jib, which allows it to lift 2t to a maximum height of 43.5m or 0.45t at a 30m radius.
All Kobelco RK-series models feature an automatic outrigger extension sensing system linked to the load moment indicator to guard against human error when the outrigger extensions have not been changed to meet different operating circumstance.
The cab has an instrument panel featuring the company’s Intelligent Total Control System. This is designed to monitor various machine functions to ensure maximum operating efficiency and safety. It also provides feedback to the operator.
Kobelco claims that it developed the first automatic swing arrest system, which detects danger zones well in advance and gently stops the swing without creating dangerous swaying of the load. This is standard on the machine from the RK250 upwards. The smaller machines are equipped with a voice alarm in advance of the load swing entering danger zones.
Another safety feature allows the operator to enter the pre-set operating zone, which prevents operation of boom and jib outside set limits.
With travel speed up to 49 km/h, selectable four- or two-wheel drive and ability to manage grades of 31 degrees, the Kobelco rough terrain crane range is no slouch. Hydro-pneumatic suspension is said to ensure smoother travel with less rolling
motion over rough terrain.
The RK250 is 2.49m wide and 3.45m high, with a machine weight of 26,495kg, enabling it to travel on highways.
Power is by a Mitsubishi 6016-TL engine delivering 184kW/2,800rpm.
