Sun-Times file Metra’s ridership is growing at a slow but steady pace — increasing by 2% since April 21 — as the commuter rail agency plans to ramp up service on many lines in anticipation of more riders on Memorial Day weekend. The transit agency reached 36,100 passenger trips on Tuesday, still just 13% of pre-pandemic levels for the same time in 2019. The March 2019 weekday average was 279,540 passenger trips. “It’s slow and it’s sure. Way up from what it was this time last year, when we were almost at the lowest point of our ridership,” James Derwinski, Metra’s CEO and exe...