Indian Railways operates on a shared track network. When one train is delayed, it blocks the track for following trains, creating a domino effect. A single delay at a major junction can cascade into dozens of delayed trains.

North India experiences severe fog from November to February. Trains must slow down significantly for safety, causing delays of 2-8 hours. Fog-related delays affect hundreds of trains daily during peak winter months.

Indian Railways conducts regular track maintenance, especially at night. Engineering blocks (temporary track closures) cause trains to wait or take alternate routes, adding to journey time.

Freight trains generate more revenue for Indian Railways and are sometimes given priority over passenger trains on shared tracks. This can cause passenger trains to wait at stations or signals.

Emergency stops, medical emergencies, passenger chain-pulling, and signal failures cause unplanned delays. Each unscheduled stoppage adds to the total delay.

Cyclones, floods, heavy rainfall, and landslides can damage tracks or make them unsafe. Trains are diverted or cancelled during severe weather events, causing major disruptions.

At busy junctions like Mumbai CST, Delhi, or Howrah, platform congestion and the sheer volume of trains can cause delays in departure and arrival.

Locomotive failures, brake issues, and signal malfunctions require trains to stop for repairs. While rare, these can cause significant delays when they occur.