The ties, which are attached to the rail tracks, have been supported by wooden ties and are not a safety risk, Pesaturo said.
"It's very safe," he said of the two rail lines, which he said see a combined average of 20,000 riders per day.
The ties were only installed 10 years ago, but are supposed to last "decades," Pesaturo said, declining to be more specific.
The Old Colony lines include stations in Brockton, Bridgewater, Middleboro, Abington, Whitman and Hanson. The CommonWealth article indicates that the tie problem is the most serious in the Bridgewater and Middleboro areas of the line. The article suggests that the problem could mean that all 150,000 concrete ties have to be replaced on the lines, which would be difficult for the cash-strapped MBTA to afford.
So far, however, there are no other ties that have been identified with problems on the Old Colony lines, Pesaturo said, emphasizing that the problem has affected a small portion of ties.
"To date, we are talking about approximately 2.7 percent of all of the ties on Old Colony," he said.
"100% of the ties have been inspected numerous times and the inspections continue," Pesaturo said. "The number of failed ties continues to grow at a rate that is expected. We are investigating new methods to identify problem ties before the cracking becomes visible to the eye, and we have had some success. This will allow us to predict the further degradation of the ties. We are continuing to take actions to replace failed ties before they adversely affect our ability to run trains. We are replacing concrete ties, adding wood ties in the cribs and installing gauge rods. We expect to begin work later this season to get rid of the highest concentration of failed ties. Although the ties were all installed at roughly the same time, there are still large sections (some almost 10 miles in length) that have virtually no tie failures evident.
"The MBTA has engaged a legal team to invoke the terms of the warranty that was part of our purchase but we will not discuss details of our legal strategy," he said.
The MBTA has Rocla concrete ties on the Greenbush line and Amtrak has both Rocla and non-Rocla ties on the Northeast Corridor located on MBTA property. Further, the MBTA has non-Rocla concrete ties on the Lowell line.
"Amtrak is dealing with the ties on the NEC," he said. "The Greenbush and Lowell ties are of a different design from those that are failing and they are showing no signs of any problems. The Greenbush ties are newer than the problem ties and the Lowell line ties are older than the Rocla ties showing problems."