Servo/Motor for barrier gate
You may purchase a servo motor with greater torque.

You may find both DC as well as AC servo's. If you are using it in a real industrial scenario I would suggest you to use the AC, as you may not have to convert the ac power to DC and these motors will need real high current. So it would be better if it works on the main voltage. I did find PANASONICs ac servo as google search result.

If you have problems with integrating the greater torque motor to your current system let me know i can help you out.