Crews this month wheeled ashore the first four of sixteen gates—each the size of a 10-story building—for the Panama Canal’s new locks, a major milestone for the $5.2-billion project. Mounted on self-propelled motorized wheel transporters, each of the 3,100-ton gates was off-loaded onto a temporary dock on the Atlantic side of the waterway, not far from the new locks that will be their permanent home.

The gates, costing about $548 million to fabricate and install, are the centerpiece of the enormous third set of locks that is being built as part of the so-called third-lane expansion of the canal. When finished, the new locks are projected to double the historic waterway’s capacity by allowing the passage of  post-Panamax-sized shipping vessels. The new gates will roll in and out from housings within the new lock structure, unlike the canal’s existing locks, which use miter-style gates that swing outward to permit the passage of vessels from one chamber to another. The second pair will arrive in November.

The arrival of the first set of new gates comes as the expansion nears the end of its sixth year of construction. According to the Panama Canal Authority—known by its Spanish acronym, ACP—more than 60% of the work on the ambitious effort has been completed, and the new lanes are slated to be opened for commercial traffic in 2015. Complications with the construction of the new locks pushed back the original completion date, which had been planned to coincide with the waterway’s centennial anniversary next year.

The 57.6-meter-long, 10-m-wide and 30.19-m-tall gates were built in Trieste, Italy, by Cimolai SpA. Upon arrival in Panama on Aug. 20, they were unloaded onto a temporary dock built near the construction site of the new Atlantic-side locks. The delicate operation was accomplished using special robotic transporters built by Sarens SPMT.

The transporters are modular platform trailers with computer-controlled wheels that are mechanically, hydraulically and electronically linked. They also will be used to move the gates into the lockhead chambers after additional components required for their operation have been installed.

“It is important that the rolling surface and the ground conditions are stable to minimize imperfections that could affect transport,” says Jose Reyes, ACP's project manager for the third set of Atlantic-side locks. “The SPMTs have a computerized system that will adapt the platform to any irregularity on the surface.”

The new locks are almost at the halfway point of completion, ACP officials say. The arrival of the gates is the most visible aspect of the locks project's electro-mechanical aspect, which is increasingly the main emphasis of the work.

To date, 67% of the concrete work on the locks is complete, and the major labor-intensive work should be done by the end of the year. In contrast, less than a third of the electro-mechanical phase has been done. The trick, officials say, is coordinating the completion of the concrete elements required for the installation of the gates and valves that comprise the electro-mechanical systems.

In addition, the water-saving basins for the locks are almost 40% complete, with work focused on the conduits that connect the basins to the locks' hydraulics system.

Outside of the locks themselves, work on the third-lane expansion is beginning to enter its final phases. The Pacific Access Channel, which will connect the new Pacific-side locks to the waterway’s main navigation channel, has been excavated to its design depth. A clay-core dam that will separate the channel from the waters of the existing Miraflores Lake will be finished in October. The dredging of Gatun Lake is expected to be completed by the end of this year.