Firecrackers set dry grass alight near the Western Railway tracks between Virar and Nallasopara at around 11.20 pm on November 8; the fire was put out within 30 minutes.
The blaze damaged 14 12-core and six six-quad signalling cables, affecting seven signals and multiple track circuits.
Fourteen suburban services were delayed on Sunday. On Monday, 35 services were cancelled and 150 delayed; UP trains towards Mumbai had to pass two signals under safety rules.
