May 9 - A Liebherr LR 11350 crawler crane owned by Scottish crane company Weldex has been used toerect the last and largest of the pylons for the modern cable car over the River Thames in London's Docklands.

The South Tower, 90 m high, was installed in the river 80 m from the bank by the crane. The cablecar, 1,100 m in length and some 50 m high, will be able to carry 2,500 people hourly in each direction over the Thames. From the Millennium Dome, the Olympic Games facility in Greenwich on the south side of the river, visitors will be able to make the new river crossing in just five minutes to the sports arena at the Royal Victoria Docks to the north of the Thames.

The original plan was for a large mobile crane to assemble the pylon from its individual parts but the condition of the subsoil on the bank of the Thames would not allow for a crane to stand directly beside the river. The reach needed, 120 m, meant that the stroke had to be thought out again and a significantly bigger machine brought in.

The LR 11350 (pictured below), a Liebherr crane with a load capacity of 1,350 tonnes, is the most powerful crawler crane in the Weldex fleet. Segments weighing up to 71 tonnes were placed in the Thames by the crane. The elegant pylon in the south part of the system, at 90 m in height and a total weight of 568 tonnes, is the largest and heaviest of the total of three steel towers.

The closeness to London's City Airport meant that periodically the crane was not allowed to work. The 96 m main boom and the 84 m luffing fly jib of the massive Liebherr crawler crane projected at a height which was significant to the airport's radar. Fog repeatedly caused delays in what was already a very tight schedule and the decision was finally taken to operate the site during the night as well. With the installation of the batteries of rollers on the head of the pylon, produced by the Austrian cable car manufacturers Doppelmayr, staff from Weldex and its crawler crane completed the helical-shaped pylon in just tendays.

In addition to this, two smaller crawler cranes, an LR 1300 and an LR 1100, were also used as taxi and assistance cranes, needed for the assembly and ballasting of the heavy-duty crane as well as for aligning and moving the individual segments of the pylon.