Terex ATs at Mexican Metro extension

The Monterrey Metro was established in 1991 and is used by almost 500,000 passengers a day. To meet continued demand for the transport service, a third line is being constructed, set to add a further nine stations and enable 26 more trains to transport 280,000 extra passengers a day.

The 7.5km-long line is being built by a consortium of Alstom Mexicana, Constructora Garza Ponce, and construction company Constructora Moyeda.

Challenges include lifting 230t U-girders, each 37m long, 1.85m high and 5.2m wide, and positioning the components at heights of 15-22m.

Arturo Moyeda Morales, chief executive of Constructuro Moyeda, said: "We chose to use two Terex all terrain cranes -- an AC 350/6 and an AC 500-2 -- because they had the capacity to lift the girders, with 350t capacity and a 64m main boom length for the AC 350/6, and 500t capacity and a 56m telescopic boom length for the AC 500-2."

The cranes are also required to move up to 2km during each day, to erect in different locations across the project.

"The cranes are roadable, needing only six flatbeds each to transport the counterweights," said Morales. "In addition, a crew of 12 people can set up the cranes in just three hours. Once a crane was moved and we had the go-ahead from the transit authorities, a lift could be done in less than 30 minutes per girder. It was the right equipment for the job."

Other challenges included working above highway and pedestrian bridges, and in between power lines.