CONCORD (CBS) – Homemade bombs on the train tracks shut down the evening commute in Concord Tuesday night. Officers stopped rail service when they found bottles full of explosive chemicals.

Police say it is not a case of terrorism.

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Trains slowly rolled through downtown Concord Tuesday night hours after some tense moments on the tracks.

In the heart of rush hour, the Concord Fire Department responded to a brush fire on the Fitchburg commuter line.

What they found was a suspicious bottle with chemicals they believe caused the fire.

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And 15 feet away they found another. Sources tell WBZ both bottles contained liquid chemicals with the potential to explode.

Transit, State and local police shut down the tracks and used flashlights to scour the area for evidence.

The second device was rendered safe by the Transit Police Explosive Unit.

Trains were cleared to go through the area by 7:00 p.m.

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No injuries were reported.