Timetable Test

Bunched trains · Chicago · Sat Oct 10

Two Green Line trains 1 min apart

At Kedzie (Green), toward Cottage Grove, between 10:36 pm and 10:37 pm. The schedule called for a train every 12 min.

Line
Green Line
Station
Kedzie (Green) (station 41070)
Direction
toward Cottage Grove
Train before
run 619, passed 10:36:39 pm
Train after
run 011, passed 10:37:39 pm
Gap
1 min (60 s)
Scheduled gap
12 min
Collector
running the whole time

Scheduled against seen

Each tick is a train at Kedzie (Green) toward Cottage Grove. The two runs either side of the bunch are labeled.

ScheduledSeen61901110:00 pm10:15 pm10:30 pm10:45 pm11:00 pm11:15 pm1 min gap

What Train Tracker said

Train Tracker reports each train's next stop. A train has passed Kedzie (Green) when its next stop moves past it.

SnapshotRun 619 (before)Run 011 (after)
10:35:09 pmnext stop Kedzie (Green)next stop Damen (Green)
10:36:09 pmnext stop Kedzie (Green)next stop Damen (Green)
10:37:09 pmnext stop California (Green)next stop Kedzie (Green)
10:38:09 pmnext stop California (Green)next stop California (Green)
10:39:09 pmnext stop Damen (Green)next stop Kedzie (Green)

Showing 5 of 5 snapshots in the gap. The full record, every train on the line minute by minute, is in 2026-10-10-green-bunch-81459.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.