As soon as the fight begins on the train stick yourself to the wall so that the cut scene shows you stuck to it.
Start blind firing your lancer at Raam. Once he reaches the end of the row of pipes (from you to him hes at the end of the pipes NOT from him to you), as soon as he rounds it on the left side start blind firing grenades until he glitches.
He will turn around and start walking and you have done the glitch successfully.
As long as Dom is set to cease fire and you're both stuck to the wall Raam will continue walking back and forth in front of the barrier and he can't shoot at you, he can still shoot though.