More than 7,000 ABSU activists squatted on railway tracks at Rangiya Bhatkuchi in Kamrup (Rural) district and at Bijni and Dangtol in Chirang district since 6 am.
ABSU organised the blockade demanding a separate directorate for Bodo medium education, appointment of sufficient teachers in Bodo-dominated schools, conduct of Teachers' Eligibility Test (TET) among others.
Kamrup (Rural) district administration has urged the students to lift the blockade and took more than 100 activists into preventive custody, official sources said.
The protestors later lifted the blockade at Rangiya Bhatkuchi but train services were yet to resume.
Among other trains, Rajdhani Express has been controlled at Guwahati station, Dibrugarh-Kolkata Kamrup Express and Purbottor Sampark Kranti Express at Kamakhya, Delhi-Dibrugarh Brahmaputra Mail at New Jalpaiguri, Howrah-Guwahati Saraighat Express at New Alipurudar and Guwahati-Thiruvanantapuram Express at Rangiya.