The MTA has spent the past few months replacing miles of jointed tracks that have been breaking under the pressure of increased ridership (and age), battling against time to avoid future derailments.

The Wall Street Journal has a long feature on how the MTA has been stepping up its efforts to replace its old joint-style rail (responsible for the thu-dunk sound you hear as a train passes) with welded subway tracks that would create a smoother, safer and quieter ride.

"That is where the weakness in that track is," Joe Leader, senior vice president for subways in the MTA's transit division told The Wall Street Journal. "Your joint bars could break. Your bolts could break."

The MTA stepped up modernization efforts after an F train derailed in Queens this spring because of a broken rail. That stretch had been slated to receive a welded rail, but as Leader told the WSJ, "We just didn't get to it in time." Other systems, like California's BART, uses almost entirely welded rail.

The MTA is installing the new rails on some of its most active corridors, including the A/C/E and B/D/F lines. Over the past ten years, the rate of breaks in the rails has increased by more than 50% on particularly trafficked tracks. So while FASTTRACK might make your commute just that much worse, remember the MTA is trying to help you live longer, by making your train less likely to derail.