The Port of Tacoma has ordered seven Kalmar CSC 340 straddle carriers for its on-dock rail operation.

Kalmar Industries will supply the Port of Tacoma on the US west coast with seven CSC 350 straddle carriers for the port's on-dock intermodal rail operations.

The straddle carriers, which have a 40-tonne single lift capability, will be engineered to stack containers three-high. They will be used to load and unload double-stack container cars at Tacoma's on-dock rail facility.

Kalmar Americas president Leif Walin says the new order will add to the existing fleet of 26 Kalmar straddle carriers at the port.

"The new machines, which will replace five older straddle carriers, are ideally suited to demanding operating conditions found at intermodal rail terminals," Walin says.

Bryon Boerner, the port's electronics technology manager, says that the straddle carriers have proven to be reliable.

"The CSC machine has a robust frame that we feel stands up to the rough service of rail yards."

Kalmar has been supplying straddle carriers to the Port of Tacoma since 1986. According to the supplier, Tacoma is the world's first on-dock rail operation to use only straddle carriers, and Kalmar and the port authority jointly produced the world's first straddle carrier operator training video.