This quest (and the ones that follow in its series) will not flag until you speak with the runner in the tower who tells you about the millionaire in Harran who, along with a pair of eggheads, has work for brave runners...
After that and some time later, as you are on your way to meet Jade at the railroad car you get a call from a pair of strangers which Flags a Side-Quest.
When you arrive at the marker the pair of strangers are waiting for you - Tolga and Fatin - and they too need you to obtain resources for them - also at the Train Yards. What they need is hooks.
When you reach the Train Warehouse find the breakable boxes and smash them to find the Hooks, then take them back to the pair and you get a CS in which they explain that they now have work to do and that they will leave some Ziplines up for you.
That completes this Side-Quest.