The CBI has arrested a railway engineer for taking a bribe of Rs 3.44 lakh, sources in the agency said on Wednesday.According to CBI sources, Vijar Kumar Yadav, a senior section engineer, was caught red-handed while taking the bribe from a contractor on Tuesday night at the Hatia Railway Station. Railway contractor Prakash Singh had raised a bill against maintenance of air conditioners. The railway engineer had allegedly sought four per cent of the total bill.Police took Yadav to his residence and checked documents related to investments and bank details. He will be produced in the CBI court after completing the search operation.