• Metro to take 7000 series out of service after defect was discovered in axle

  • Discussion related to DC area passenger rail services from Northern Virginia to Baltimore, MD. Includes Light Rail and Baltimore Subway.
Discussion related to DC area passenger rail services from Northern Virginia to Baltimore, MD. Includes Light Rail and Baltimore Subway.

Moderators: mtuandrew, therock, Robert Paniagua

  by Sand Box John
 
mmi16
Are the 7000's still running with their 'as delivered' axle/wheel sets? Or has WMATA maintenance been replacing them and are WMATA personnel doing the pressing of the wheels on the axles?


The oldest cars haven't been in service long enough justify the replacement of the wheels after normal wear. This amusing line was in a Washington Post article on how WMATA was dealing the issue.
Metro tried to address the issue by increasing the pressure used to push wheels onto axles after more than 490 of the 748 cars were delivered, officials said. Still, the defects appeared in cars after the modifications were made.
The repressing of the wheels on the axles at a higher pressure ain't going fix it as the interference fit was not tight enough in the first place.
  by STrRedWolf
 
wrivlin wrote: Thu Oct 28, 2021 3:14 pm Any insight into why WMATA isn't running any four-car trains? Even if it doesn't change capacity, it would at least reduce headways.
You're running less 6 or 8 car trains, which means less operators to run them. Why pay more operators when you really don't need 'em.
  by mmi16
 
Sand Box John wrote: Tue Oct 26, 2021 6:49 pm mmi16
Are the 7000's still running with their 'as delivered' axle/wheel sets? Or has WMATA maintenance been replacing them and are WMATA personnel doing the pressing of the wheels on the axles?


The oldest cars haven't been in service long enough justify the replacement of the wheels after normal wear. This amusing line was in a Washington Post article on how WMATA was dealing the issue.
Metro tried to address the issue by increasing the pressure used to push wheels onto axles after more than 490 of the 748 cars were delivered, officials said. Still, the defects appeared in cars after the modifications were made.
The repressing of the wheels on the axles at a higher pressure ain't going fix it as the interference fit was not tight enough in the first place.
Any idea of just how much interference there is supposed to be between wheel and axle?
  by Sand Box John
 
mmi16
Any idea of just how much interference there is supposed to be between wheel and axle?


Not knowing the diameter of the axle and a number dimensions in the area of the wheel hub I can't give an exact dimension. it is some where around 0.2 – 0.36 mm, 0.0141" - 0.0007" That's a range of 14 one thousands of an inch. The interference fit of the outside diameter of a car wheel bearing to the spindle is in the lower quarter of that range.
  by danib62
 
STrRedWolf wrote: Thu Oct 28, 2021 7:51 pm You're running less 6 or 8 car trains, which means less operators to run them. Why pay more operators when you really don't need 'em.
Those operators are getting paid either way. Right now they're just sitting around. Union work rules don't just let you furlough most of your workforce without pay because your trains are broken.
  by STrRedWolf
 
danib62 wrote: Tue Nov 02, 2021 10:27 am
STrRedWolf wrote: Thu Oct 28, 2021 7:51 pm You're running less 6 or 8 car trains, which means less operators to run them. Why pay more operators when you really don't need 'em.
Those operators are getting paid either way. Right now they're just sitting around. Union work rules don't just let you furlough most of your workforce without pay because your trains are broken.
Depends on if they're classified full-time or part-time. Depends on the union's CBA. Hell, I'll be surprised if they got "Weekend Warriors" on the payroll (like MTA Maryland did for a while).
  by danib62
 
You’re right it does depend on the CBA and under the current one there are lots of operators sitting around right now waiting to “run as directed”. I have this on good authority.
  by Sand Box John
 
Seems stupid to not have backup plans in place encase of some unforeseen event. WMATA should have made a deal with MWAA and stored those cars at Dulles Yard and anything else in other yards and shops during Rockville station canopy project. The service and inspection capacity at Shady Grove has been doubled sense that facility was originally built, Brentwood by one third with Glenmont unchanged.
  by Sand Box John
 
STrRedWolf
Unfortunately those tracks were not tied in just yet, so they couldn't have.


Phase II of the Silver line is in fact tied in, its been that way for at least two an half years. it's only the signal and train control system that is not fully operational. Nothing physically preventing WMATA from dead heading any rolling stock along the unopened part of the Silver line.