Melbourne

CREATING the world's largest moving robots to transport iron-ore across the vast Australian Outback is proving more complex and time-consuming than expected for Rio Tinto Group, fuelling doubts the technology can deliver promised returns as major rivals defer similar investments.

Rio, which gets more profit from iron-ore than anything else, is already two years behind schedule with a US$518 million effort to deploy automated trains on its 1,700 kilometres of track. While the system was designed to save money by expanding capacity and reducing labour costs, instead the delays mean the producer has cut output forecasts, and raised questions about whether the project is viable, according to Deutsche Bank AG.