by doepack
BUMPY AS 'L'
Riding the CTA's rails may leave passengers feeling a bit green, study finds
By Jon Hilkevitch,
Tribune transportation reporter
Tribune staff reporter James Janega contributed to this report.
Published November 16, 2006
Would Humpty Dumpty arrive feeling a bit scrambled after riding a CTA train?
A company that figures out how much packaging is needed to protect computer chips trucked over bumpy roads in China released a study Wednesday suggesting CTA passengers shouldn't put all their eggs in one basket while riding on the Blue Line.
Unless, perhaps, the eggs are swaddled in bubble wrap, or destined to become omelets.
CTA rail cars are most likely to shake, rattle and roll passengers on the Blue and Orange Lines, the "L" ride-quality study by Lansmont Corp. concluded.
"These are attention-catching types of events of at least 1 G of vertical acceleration. Enough not just to bump you up vertically, but to move your, uh, butt cheeks in one direction or the other--up, down, left, right, front, back," said Eric Joneson, a Lansmont packaging engineer who works at the California-based company's testing lab in Lansing, Mich.
"The Blue Line by far was the most severe," he said.
A ride by a Tribune reporter along the Blue Line Wednesday between downtown and O'Hare International Airport found almost every rider braced against nearby seats or leaning heavily against walls.
"It's terrible, especially when it's crowded," said Elizabeth Fitzgerald of the Northwest Side. "Particularly before this stop," she added as she stepped off the lurching train at Montrose. Clattering and swaying, it rushed away.
Lansmont's testing on CTA trains, which used a field data recorder developed by the Monterey, Calif., engineering company to measure dynamic shock and vibration, found the best ride quality overall on the Brown, Yellow and Purple Lines, comparable in spots to riding in a car on Germany's Autobahn.
The Pink Line, the CTA's newest route, scored the largest individual bump. The Pink Line also racked up five of the top 10 bumps among the eight CTA rail lines, according to the study by Lansmont, which measures shock and vibration levels to advise clients how to safely transport products ranging from potato chips to circuit boards for nuclear warheads.
If the bumps and swaying were enough to raise researchers' eyebrows, they did little to rattle some regular riders. On the Pink Line, medical workers jumped aboard inbound from Polk Street, and Loop workers cruised outbound past Ashland without a care.
Numerous factors--the condition of a specific train, the operator's proficiency and how an individual passenger's weight is distributed--play a role in determining the influence of hard turns and other often sudden changes in the speed and direction of CTA trains.
But data from the study back up why some CTA riders might feel tired or occasionally a tad queasy after getting off the train.
A ride on the Pink Line just west of the Ashland/Lake station produced the biggest momentary bump--2.87 Gs of vibration. The Titan "hyper coaster" at the Six Flags Over Texas theme park registers a top sustained force of 4.5 Gs.
The largest recorded individual bump on the Yellow Line, meanwhile, was only 0.44, the study found.
"Anything over 2.5 Gs would feel like going over a speed bump at a good clip. It would be surprising to feel that type of thing on a passenger train," said Douglas Adams, an associate professor of mechanical engineering at Purdue University who studies vibration in automotive systems.
Such a force of 2.5 Gs, if applied quickly like the jerky motion of a CTA train, would lift an egg off a seat and cause it to break upon landing, Adams said.
As for commuters, it depends.
"The impact of coming back down into your seat is going to feel less harsh to somebody with extra padding than somebody who is thinner in frame," he said.
Lansmont conducted the train ride quality study without the consent or knowledge of the CTA, in preparation for a trade show this year to show off the company's newest device, the SAVER 9x30 triaxial accelerometer, said Rick Kamel, a Lansmont spokesman.
"We are willing to share the information with the CTA free of charge to help them focus where maintenance might be needed," Kamel said.
CTA officials said Lansmont has not contacted the agency.
The CTA said the study, which was conducted over two days and involved gathering measurements during a roundtrip on each of the eight rail lines, represents at best a snapshot, rather than a comprehensive analysis, of track and rail-car conditions and train operator performance.
"We do regular rail grinding to prevent bumps in the tracks and repairs to flat spots on train wheels to make the ride smoother," said CTA spokeswoman Noelle Gaffney.
Lansmont's monitoring equipment recorded when shocks and vibrations occurred and pinpointed locations using a global-positioning system device, officials said.
The 35-year-old company counts the U.S. Navy, Boeing, Dell Computers, Harley-Davidson Motorcycles, Kellogg's cereals and Pringle's potato chips among its customers.
Intel hired Lansmont to test the quality of roads and map trucking routes between the company's computer chip production plant in Shanghai and Qian, China, Kamel said.
The company advised the Navy how to prevent damage to circuit boards on its nuclear weapons during shipping.
"And you'd be surprised how much science goes into shipping a Pringle's," Joneson said.
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jhilkevitch@...
Copyright © 2006, Chicago Tribune
Riding the CTA's rails may leave passengers feeling a bit green, study finds
By Jon Hilkevitch,
Tribune transportation reporter
Tribune staff reporter James Janega contributed to this report.
Published November 16, 2006
Would Humpty Dumpty arrive feeling a bit scrambled after riding a CTA train?
A company that figures out how much packaging is needed to protect computer chips trucked over bumpy roads in China released a study Wednesday suggesting CTA passengers shouldn't put all their eggs in one basket while riding on the Blue Line.
Unless, perhaps, the eggs are swaddled in bubble wrap, or destined to become omelets.
CTA rail cars are most likely to shake, rattle and roll passengers on the Blue and Orange Lines, the "L" ride-quality study by Lansmont Corp. concluded.
"These are attention-catching types of events of at least 1 G of vertical acceleration. Enough not just to bump you up vertically, but to move your, uh, butt cheeks in one direction or the other--up, down, left, right, front, back," said Eric Joneson, a Lansmont packaging engineer who works at the California-based company's testing lab in Lansing, Mich.
"The Blue Line by far was the most severe," he said.
A ride by a Tribune reporter along the Blue Line Wednesday between downtown and O'Hare International Airport found almost every rider braced against nearby seats or leaning heavily against walls.
"It's terrible, especially when it's crowded," said Elizabeth Fitzgerald of the Northwest Side. "Particularly before this stop," she added as she stepped off the lurching train at Montrose. Clattering and swaying, it rushed away.
Lansmont's testing on CTA trains, which used a field data recorder developed by the Monterey, Calif., engineering company to measure dynamic shock and vibration, found the best ride quality overall on the Brown, Yellow and Purple Lines, comparable in spots to riding in a car on Germany's Autobahn.
The Pink Line, the CTA's newest route, scored the largest individual bump. The Pink Line also racked up five of the top 10 bumps among the eight CTA rail lines, according to the study by Lansmont, which measures shock and vibration levels to advise clients how to safely transport products ranging from potato chips to circuit boards for nuclear warheads.
If the bumps and swaying were enough to raise researchers' eyebrows, they did little to rattle some regular riders. On the Pink Line, medical workers jumped aboard inbound from Polk Street, and Loop workers cruised outbound past Ashland without a care.
Numerous factors--the condition of a specific train, the operator's proficiency and how an individual passenger's weight is distributed--play a role in determining the influence of hard turns and other often sudden changes in the speed and direction of CTA trains.
But data from the study back up why some CTA riders might feel tired or occasionally a tad queasy after getting off the train.
A ride on the Pink Line just west of the Ashland/Lake station produced the biggest momentary bump--2.87 Gs of vibration. The Titan "hyper coaster" at the Six Flags Over Texas theme park registers a top sustained force of 4.5 Gs.
The largest recorded individual bump on the Yellow Line, meanwhile, was only 0.44, the study found.
"Anything over 2.5 Gs would feel like going over a speed bump at a good clip. It would be surprising to feel that type of thing on a passenger train," said Douglas Adams, an associate professor of mechanical engineering at Purdue University who studies vibration in automotive systems.
Such a force of 2.5 Gs, if applied quickly like the jerky motion of a CTA train, would lift an egg off a seat and cause it to break upon landing, Adams said.
As for commuters, it depends.
"The impact of coming back down into your seat is going to feel less harsh to somebody with extra padding than somebody who is thinner in frame," he said.
Lansmont conducted the train ride quality study without the consent or knowledge of the CTA, in preparation for a trade show this year to show off the company's newest device, the SAVER 9x30 triaxial accelerometer, said Rick Kamel, a Lansmont spokesman.
"We are willing to share the information with the CTA free of charge to help them focus where maintenance might be needed," Kamel said.
CTA officials said Lansmont has not contacted the agency.
The CTA said the study, which was conducted over two days and involved gathering measurements during a roundtrip on each of the eight rail lines, represents at best a snapshot, rather than a comprehensive analysis, of track and rail-car conditions and train operator performance.
"We do regular rail grinding to prevent bumps in the tracks and repairs to flat spots on train wheels to make the ride smoother," said CTA spokeswoman Noelle Gaffney.
Lansmont's monitoring equipment recorded when shocks and vibrations occurred and pinpointed locations using a global-positioning system device, officials said.
The 35-year-old company counts the U.S. Navy, Boeing, Dell Computers, Harley-Davidson Motorcycles, Kellogg's cereals and Pringle's potato chips among its customers.
Intel hired Lansmont to test the quality of roads and map trucking routes between the company's computer chip production plant in Shanghai and Qian, China, Kamel said.
The company advised the Navy how to prevent damage to circuit boards on its nuclear weapons during shipping.
"And you'd be surprised how much science goes into shipping a Pringle's," Joneson said.
----------
jhilkevitch@...
Copyright © 2006, Chicago Tribune
--Dorian--
