Delay Index
| Brake Malfunction | Delays caused by brake being activated. |
| Track Maintenance | Delays caused by track work, rails replacement, and removing things on tracks. |
| Disruptive Passenger | Delays caused by disruptive passenger on trains or in stations. |
| Mechanical Problem | Delays caused by mechnical malfunction and door malfunction. |
| Medical Emergency | Delays caused by passenger/staff in need of medical help. |
| Signal Malfunction | Delays caused by signal malfunction. |
| Power Outage | Delays caused by power outages. |
| Switch Malfunction | Delays caused by switch problem. |
| Cleaning Trains | Delays caused by the crew removing trains in need of cleaning. |
| Police Activity | Delays caused by NYPD conducting investigations. |
| Fire or Flooding | Delays caused by FDNY activity, track on fire, smoke in trains, water on tracks. |
| Other | Rare events such as making way for garbage trains to run on tracks, communications issues, etc. |
| Unknown Cause | Delays with unspecified cause. |