Work performed under the first contract, Contract C72CN01, included approximately seven (7) miles of “Rail De-stressing” on the outbound Track #1 between milepost 33 in Westboro and milepost 43 in Worcester. This phase of the project was advertized in the spring of 2014 and awarded to JF White Construction Co. Work commenced in August 2014 and was completed in October 2014.
Work to be performed under the second contract, Contract C72CN02, consists of approximately seventeen (17) miles of “Rail De-stressing” on inbound Track #2 beginning at milepost 4 in Allston and continuing west to milepost 21 in Framingham. Contract C72CN02 was advertised in the fall of 2014 and awarded to JF White Construction Co. in April 2015. “Rail De-stressing” work commenced in early May and is anticipated to be complete in July 2015.
Work to be performed under the third contract, Contract C72CN03, consists of the replacement of approximately fifteen (15) miles of existing sections of 131# (pound) rail with new 136# (pound) rail on outbound Track #1 located between milepost 21 in Framingham and milepost 45 in Worcester. It is expected that this work will immediately follow the completion of Contract C72CN02, commencing in July 2015 with project completion by the end of 2015.
F-line to Dudley via Park wrote:What is rail "de-stressing"? Is this west-of-Framingham closeout work from the CSX handoff for elimination of the last lengths of CWR subject to summer heat speed restrictions. And/or closeout work for a west-of-Framingham track class uprate opening up some real stretches of 79 MPH?
This line has so much potential in it
dbperry wrote:I read up on this a few years ago when we started to get hit with the continuous 'heat delays' on the Framingham Worcester line.
Here's what I've been able to piece together:
CWR has a Rail Neutral Temperature ("RNT") - the temperature at which there are no thermally induced loads (compression or tension) on the rail. Typically this is the temperature of the rail when it is installed. When it gets hotter than RNT, the rail wants to stretch, and when it gets colder, the rail wants to compress. Stretch too much and it buckles, compress too much and it snaps leaving a gap.
The ideal Rail Neutral Temperature is quite hot - different sources I saw ranged from 81 to 90 to 115. I think there is regional variation for that value. A hot RNT leaves enough 'room' on either side that the rail won't buckle in hot weather or snap in cold weather. Basically the concern is more on the hot side - so having a higher 'starting point' (as in rail neutral temperature) provides more capacity for hotter temperatures to not affect the rail.
For whatever reason, either Conrail or CSX didn't have documentation of the rail neutral temperature or didn't have a high enough rail neutral temperature for the B&A. The project description at the link above hints at this - I never bothered to get the actual bid documents to see if the Framingham Worcester situation is better explained.
So rail stressing or destressing (words which seem to be used somewhat interchangeably, I can't figure out the difference) is the practice of essentially changing the rail neutral temperature. The rail is released from the ties and heated to the desired temperature. This usually requires cutting a small segment from the rail to allow it room to expand. Once it is at the correct temperature, it is reaffixed to the ties and welded to the next section. I think they use some kind of anchor at each weld point to keep each segment in place at the new rail neutral temperature - perhaps forever, or maybe just until the whole section of rail is destressed.
That's what I recall from my reading...this is the only thing I bookmarked. I know I found lots more with google.
https://www.fra.dot.gov/Elib/Document/3036
MBTA F40PH-2C 1050 wrote:What should be done is what Amtrak has done in times past on the NEC....cancel all weekend service for 2 or 3 weekends in a row, and perform a maintenance blitz on the line, get as much done in 2, 12 hour shifts/per day, in 2 consecutive weekends
Heat restrictions are issued when ambient temps (measured in Fram, Worc, Boston) reach 85. We alert as soon as this happens.
Heat restrictions are lifted as soon as ambient temperature drops below 85.
dbperry wrote:I also got some answers from the twitter folks.
My question was: Since the info page (http://www.mbta.com/about_the_mbta/t_projects/default.asp?id=6442454462) indicates that phase 1 was completed last year, will heat restrictions still affect the line from milepost 33 to milepost 45 (Worcester)?
Answer from @MBTA_CR: Yes. Heat restrictions will be implemented for entire line until entire project is done. "The destressing aspect is complete in that stretch but other work still ongoing."
I have other questions I'll be asking them...
Do you have questions, concerns or feedback you would like to share?
Join us at our Spring Meet the Managers event for the opportunity to speak with some of the members of the Keolis Management Team!
Managers from various departments will be in attendance to respond to any questions, and provide updates on ongoing or upcoming service initiatives.
Stop by one of the following sessions:
South Station:
Wednesday, June 17th, 4p-6p
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Wednesday, June 17th, 4p-6p
North Station:
Thursday, June 18th, 4p-6p
dbperry wrote:Answer from @MBTA_CR: Yes. Heat restrictions will be implemented for entire line until entire project is done. "The destressing aspect is complete in that stretch but other work still ongoing."
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