NICK BLUMBERG WHO IS REPORTING FROM EDGEWATER.

>> Reporter: PARIS, AS MENTIONED EARLIER, THE CTA IS IN THE MIDST OF A MUCH-NEEDED OVERHAUL OF THE RED AND PURPLE LINE ON THE NORTH SIDE.

I CAUGHT UP WITH CTA'S TAMMY SHAY AND I ASKED HER ABOUT THE YEARS LONG MODERNIZATION EFFORT.

>> WE HAVE REBUILT MORE THAN A MILE OF TRACK STRUCTURE, WHICH INCLUDES BUILDING PURPLE AND RED LINE TRACKS THAT ARE IN THAT AREA.

WE ARE ALSO GETTING STARTED BUILDING FOUR NEW REDLINE STATIONS ALONG BERWYN AND BRYN MAWR.

>> Reporter: SO THIS IS A MUCH DIFFERENT PROFILE THAN WE ARE USED TO.

THIS WILL ACTUALLY CREATE SPACE BENEATH TRACKS.

WHAT IS THE CTA PLANNING TO DO WITH IT?

>> THERE WILL BE NO OBSTRUCTIONS IN THE STREETS, WHICH WILL BE GREAT FOR SIGHTLINES AND DRIVERS.

BUT THERE WILL BE A NEW SPACE UNDER THE TRACKS FOR THE FIRST TIME IN 100 YEARS SINCE THE L LINE WAS BUILT.

WE WILL ASK THE COMMUNITY WHAT THEY WANT BLOCK BY BLOCK.

IT MIGHT BE MORE PARKING OR SPACE FOR COMMUNITY MARKETS.

SO WE ARE EXCITED!

IN WHAT CITY CAN YOU JUST HAVE BRAND-NEW SPACE TO OFFER PEOPLE?

>> Reporter: WHERE DO THINGS STAND IN TERMS OF REBUILDING THE TWO SIDES OF THE TRACK?

>> YEAH, WE ARE BUILDING THIS PROJECT IN TWO STAGES.

THE FIRST STAGE WAS BUILDING THE NORTHBOUND RED AND PURPLE LINE TRACKS.

THAT IS THE EXCITING PART.

ONCE WE COMPLETE THAT LATER THIS SUMMER, WE WILL PUT THE NEW TRACKS INTO SERVICE, WHICH MEANS OUR CUSTOMERS GET TO WRITE ON THEM FOR THE FIRST TIME.

WE CANNOT WAIT FOR THEM TO KNOW THE DIFFERENCE.

THEN WE WILL START BUILDING THE SOUTHBOUND TRACKS BETWEEN BRYN MAWR AND THE STATION HOUSES.

>> SO BUILDING THE STATION HOUSE AND SOUTHBOUND TRACKS, WHAT IS THE TIMELINE MIKE TO WRAP ALL OF THESE UP?

>> THIS WILL PROBABLY TAKE TWO YEARS TO COMPLETE.

WE ARE STILL ON TIME FOR 2025.

>> Reporter: IN TERMS OF THE FURTHER WORK LOOKING NORTH, WHAT CAN WE EXPECT FROM THAT?

>> WE ARE A MULTIPHASE PROJECT.

WE ARE IN PHASE ONE, AS WE HAVE BEEN TALKING ABOUT.

WE ARE AT LEAST PROBABLY A COUPLE MORE PHASES, WHICH INCLUDES BUILDING FROM THORNDALE ALL THE WAY NORTH TO LINDEN AND WELL BACK!

THE OTHER STRETCH WE NEED TO BUILD IS AROUND SHERIDAN STATION.

THAT IS KIND OF AN OLD STATION THAT WE WANT TO REBUILD AND MAKE ACCESSIBLE AS WELL.

>> Reporter: THOSE NEW NORTHBOUND TRACKS THAT CHASE MENTIONED THAT ARE ABOUT TO GO INTO SERVICE THIS YEAR, THEY ARE HIGHER THAN MOST L TRACKS AROUND THE CITY.

THEY ALSO HAVE NOISE WELLS ON BOTH SIDES FOR THE FIRST TIME THAT WILL CUT DOWN ON A LOT OF THE ICONIC CTA