Pipeline Restarted After Planned Shutdown

The Trans Alaska Pipeline System was restarted at 5:45 p.m. Monday, June 20, 2005 after workers completed a series of projects during a scheduled maintenance shutdown. The shutdown lasted nearly 36 hours. Key work activities included installing infrastructure at Pump Station 4 to prepare the station for Alyeska’s Strategic Reconfiguration project, replacement of two pig trap valves at Pump Station 4, and installation of a 48-inch mainline check valve at Pump Station 7. In addition, approximately 40 other work tasks were performed during the shutdown at other pump stations, remote valve sites, and at the Valdez Marine Terminal.

This was the first of two maintenance shutdowns scheduled this summer. The second shutdown is planned for July 23-24 and will also last approximately 36 hours.

Alyeska conducts line-wide shutdowns nearly every year to allow maintenance crews time to work on projects simultaneously along the pipeline and at the terminal. These shutdowns coincide with the producers’ routine maintenance on equipment and facilities on the North Slope.

The shutdown work was completed safely with no injuries or spills on the pipeline.

Below are some photos from the work at Pump Station 4.

With the aid of an “air skate”, workers move a 48-inch valve into Pump Station 4. The air skate works similar to a hovercraft with a compressor feeding air into the system, allowing it to "float" this 58,000 lb valve.


Work crews bolt a new 48” valve to the mainline pipe. A pig trap vessel is shown in the foreground. Alyeska uses mechanical devices called "pigs" to clean the pipe walls and evaluate pipeline integrity. The pigs are received through the trap as it travels the 800 miles from Prudhoe Bay to Valdez.


A new piping spool and valve assembly is positioned in order for workers to connect the two pipe ends. The connection of the pipe fittings will prepare Pump Station 4 for new pump driver packages and other process equipment.



Alyeska is in the process of updating four critical pump stations (1, 3, 4 and 9) with electrically driven crude oil pumps combined with increased automation and upgraded control systems.

In order to prepare the pump stations, piping systems and valves need to be installed to accommodate the new equipment.


A hydraulic device is used to fasten the piping system at Pump Station 4 to the mainline 48-inch pipeline. Once the ends of the pipe are matched up, work crews bolt the two ends together.


A hydraulic device holds the Pump Station 4 piping system in place, connecting the two pipe ends.