CHICAGO — The CTA Yellow Line is set to reopen Friday morning, seven weeks after a crash on the tracks injured more than a dozen people and left the train line to Skokie closed. CTA has attributed the nearly two-month closure to testing the agency was conducting on the line and a desire to have National Transportation Safety Board investigators return to Chicago for a second visit, as questions lingered about the factors contributing to the crash and whether it could have been prevented. CTA’s reopening of the line, also known as the Skokie Swift, comes with several new safety measures, includ…