At Clark/Lake, toward O'Hare, between 9:33 pm and 9:34 pm. The schedule called for a train every 9 min.
Line
Blue Line
Station
Clark/Lake (station 40380)
Direction
toward O'Hare
Train before
run 236, passed 9:33:39 pm
Train after
run 134, passed 9:34:32 pm
Gap
1 min (52 s)
Scheduled gap
9 min
Collector
running the whole time
Scheduled against seen
Each tick is a train at Clark/Lake toward O'Hare. The two runs either side of the bunch are labeled.
What Train Tracker said
Train Tracker reports each train's next stop. A train has passed Clark/Lake when its next stop moves past it.
Snapshot
Run 236 (before)
Run 134 (after)
9:32:09 pm
next stop Clark/Lake
next stop Clark/Lake
9:33:09 pm
next stop Clark/Lake
next stop Clark/Lake
9:34:09 pm
next stop Grand (Blue)
next stop Washington
9:35:09 pm
next stop Grand (Blue)
next stop Division
9:36:09 pm
next stop Chicago (Blue)
next stop Division
Showing 5 of 5 snapshots in the gap. The full record, every train on the line minute by minute, is in 2026-10-10-blue-bunch-77671.json.
Check it yourself
Scheduled times come from CTA's GTFS schedule for Sat Oct 10. Positions come from Train Tracker, polled once a minute.
The raw records above are exactly what CTA's servers returned. How the numbers are worked out.