Railway spokesman T. Rabha said the bomb was found in the town of Tihu, 80 kilometres (50 miles) west of Assam's main city, Guwahati.
He said bomb disposal squads were at the station. No further details were immediately available.
The bomb scare came as the oil- and timber-rich state was paralysed by a one-day strike protesting an Indian Army crackdown on an influential separatist group, officials said.
"Shops and businesses, educational institutions and banks are closed, while most public and private transport are off the roads," a police spokesman said.
The protest against New Delhi's decision to resume anti-insurgency operations against the banned United Liberation Front of Asom (ULFA) was organised by a newly formed pro-rebel civil society group calling itself the People's Committee for Peace Initiatives.
"We want the government to begin peace talks by immediately stopping the military offensives against the ULFA," said the group's spokesman, Lachit Bordoloi.
The peace process came to an abrupt halt last week when a group of 11 civil society leaders nominated by the separatists to negotiate with New Delhi pulled out of talks, after the government formally ended a six-week cease-fire.
The group had held three rounds of talks in the past year in an effort to end three decades of insurgency.
But the cease-fire lapsed after the rebels refused to commit to direct peace talks in writing. The militants demanded that five of their jailed leaders first be released.
Violence has since escalated and more than 10,000 people have lost their lives to the insurgency in mineral-rich Assam in the past two decades.

Copyright AFP (Agence France-Presse), 2006