Fact Sheet: Portland Aerial Tram Maintenance Work
02/24/11 Portland, Ore.
The Portland Aerial Tram will be out of service for scheduled maintenance and a required annual inspection beginning after 10 p.m. on Thursday, Aug. 30, through Monday, Sept. 3. It will reopen on Tuesday, Sept. 4, at 6 a.m.
As anticipated, the 7,546-foot continuous-loop haul rope, which moves the passenger cabins between the upper and lower terminals, has stretched in the eight months the Tram has been in service. It needs to be shortened by 25 to - 28 feet and then respliced. This will not have to be done again for the remaining lifetime of the rope, which is expected to be anywhere from eight to 12 years. The lifetime of the rope will be determined by the number of times it cycles through the drive system circuit. So far the rope has completed in excess of 34,000 cycles and the Tram’s drive system engine has operated for more than 2,400 hours. The required annual inspection of the haul rope also will be performed during the closure.
Haul ropes stretch more rapidly in the first year of service because their polyfiber cores get compressed faster when they are new. The core is impregnated with oil, which leaches out as it is squeezed and lubricates the areas between the eight strands of galvanized steel wire wrapped tightly around the core to form the rope. The lubrication continues throughout the life of the rope and is vital for maintaining its flexibility so that it can easily bend around the bullwheels and through the drive system.
How and When:
Thursday, Aug. 30, after 10 p.m. — Both Tram cabins will be detached from the haul rope and parked at the lower terminal (0698 S.W. Gibbs St., the intersection of S.W. Gibbs and S.W. Moody) adjacent to the OHSU Center for Health & Healing. Rigging for the splicing bridge will be laid out.
Friday, Aug. 31 — The 160-foot splicing bridge – dubbed “the stairway to heaven” by construction crews when it was first used last year during construction of the Tram – will be erected by a boom truck crane in front of the lower Tram terminal on the cabin-one (the Walt Reynolds), or south, side. The work will not interfere with the Portland Streetcar, whose tracks run between the lower Tram terminal and the Center for Health & Healing. The splicing bridge has been transported to Portland from Salt Lake City, where it has been warehoused by Doppelmayr CTEC.
Saturday, Sept. 1 — Eight to 12 Doppelmayr CTEC workers will ascend the splice bridge, unravel the current splice, cut the rope and then resplice it. When completed the respliced section will be about 134 feet long, or about 1,200 times the 1.34 inch diameter of the haul rope and will be nearly as strong as any other part of the rope.
PHOTOGRAPHERS: Doppelmayr officials advise that the best visuals are likely to be on Saturday afternoon when the resplicing begins. The schedule that day, however, remains somewhat fluid.
Sunday, Sept. 2 — Final resplicing work will be completed and the rigging removed. The haul rope then will be passed slowly through an electromagnetic machine at the lower terminal as part of the annual inspection. The machine functions much like an X-ray and is used to search for any significant anomalies, or flaws, in the rope.
Monday, Sept. 3 — The splicing bridge will be dismantled and removed. The Tram cabins will be thoroughly cleaned. And the Tram will be ready to go again.
Tuesday, Sept. 4 — Tram reopens at usual time, 6 a.m.
Haul rope length: 7,546 ft.
How much it will be shortened: 25 ft. to 28 ft.
Length of splice: 134 ft.
Diameter of haul rope: 1.34 inches
Length of splicing bridge (aka stairway to heaven): 160 ft.
Composition of haul rope core: oil-impregnated polyfiber
Total number of Tram users since opening in January, through July: 672,179
The Tram is operated by Doppelmayr CTEC under a contract with Oregon Health & Science University. For more details about the tram, go to www.portlandtram.org