S. Srinivas, 22, was travelling on a Dadar-Thane local train when some yellow colour powder was thrown at him from a train plying in the opposite direction.
Another commuter, G. Nityanand Ganpati, 26, had died almost instantly when he and five others lost their balance after being hit Monday night on the Kurla-Sion section of Central Railway.
Though suburban trains were mostly deserted Wednesday, the Government Railway Police maintained a tight vigil near suburban railway lines, stations and overbridges to prevent recurrence of the Monday incident.
The yellow powder, samples of which have been sent for chemical analysis, caused severe injuries and burning sensation in the eyes of the commuters travelling on the footboard, causing them lose grip and fall down.
In view of the tragedy, Maharashtra Chief Minister Prithviraj Chavan, city mayor Sunil Prabhu and police have appealed to people to celebrate a safe holi without using dangerous chemical powders.