The two passenger trains are said to have crashed near the Government Center station right under downtown Boston. Boston Police Department have announced that the station has been evacuated.
A spokesman for the Boston police department also said that no deaths have been reported as a result of the crash although approximately 40 commuters are reported to be injured.
Initial reports say that one train hit another train that was stopped, from behind.
Boston emergency officials have declared a Phase 2 mass casualty incident and that all passengers have been removed from the trains and the injured are being treated at the scene and transported to local hospitals.