Three security guards including an Ansar member of Darshana International Railway Station were hacked to injuries by miscreants in the yard on Saturday night.
The injured were identified as Hafizur Rahman, 38, Abdur Razzak 50, and Sanjit Kumar Biswas, 35.
Sources at the railway station said a gang of miscreants numbering seven to eight attacked the on-duty security guards and hacked them indiscriminately leaving the trio critically injured.
Being rescued, the injured were admitted to Chuadanga Sadar Hospital, reports a news agency.
As the condition of Hafizur and Razzak went critical, duty doctors at the hospital referred them to Dhaka.
Meanwhile, Darshana police in a drive detained five in connection with the attack.