The Portland Aerial Tram will be out of service for Thanksgiving Thursday, Nov. 22, and Friday, Nov. 23. Then it will close again on Saturday, Dec. 1, and Saturday, Dec. 8, for scheduled maintenance on the track ropes that carry the Tram cabin carriages. And it will be closed for Christmas, Tuesday, Dec. 25.

For up-to-the minute information about the Tram and its operating hours, go to www.portlandtram.org.

Shuttle bus service will be available between the Oregon Health & Science University Center for Health & Healing in the South Waterfront during the Dec. 1 and Dec. 8 maintenance closures.

The maintenance closures are necessary because the track ropes have reached the end of their normal stretch-and-settle-in period, which occurs during the first year of operations, and they need to be "retensioned." Similar work on the haul rope, which pulls the cabins and is separate from the track ropes, was completed over the Labor Day weekend. When the retensioning of the track ropes is completed, the work is not likely to be required again.

The track ropes will be retensioned by taking up about 20 inches of slack in each, wrapping the extra lengths around stationary bollards in the Tram's engine room at the lower terminal and then reanchoring them. The operation will require approximately 121,000 pounds of tension to pull up the slack in each rope. This will be accomplished by using very large, multiple-wheel sheaves with wire rope reeving and a portable winch as well as manual labor to move the 55 mm diameter steel rope around the bollards.

Work on the two southern track ropes – the ones that carry Cabin 1, the Walt Reynolds – will begin after the Tram cabins complete their last runs on Friday, Nov. 30, and will continue through that weekend. The Tram will resume regular service at 6 a.m. on Monday, Dec. 3, and will remain on the normal schedule through Friday, Dec. 7. The two northern track ropes – which carry Cabin 2, the Jean Richards – will be retensioned over the Dec. 7 through Dec. 9 weekend. Regular Tram service then will resume at 6 a.m. on Dec. 10.