alright. first off, theres a turn right after the tunnel at like 30 seconds, there is a second turn right before the first pulse wave hits the train. second, you can’t tell if it’s turning or not at the end because the wave of energy pretty much blocks everything else out. Second, there is some time between when EP1 ends and EP2 begins. that would be the time between when the wave hit, and when you woke up from blacking out we don’t know how long that was, and we don’t know the events that happened with that. for all we know, Alyx became conscious long before gordon did while the train was still going and dragged him inside so nothing more would happen to him. It wouldn’t be the first time Alyx came back to her conscious state long before we did mind you (remember the beginning of episode 1). the train could have rolled off the tracks after you were dragged inside the cart. the vortigaunts could have put you in a different car to protect you from dying, hell the G-man could have put you in a different cart to keep you from dying, since they both see you as an invaluable tool and neither want you dead. the explosion could have propelled you back into the car (under the assumption that you were standing directly in front of the door) before tossing the train off the tracks. bear in mind that when we wake up the train is a MUCH further away from the citadel than when the wave hit and we somehow ended up on top of a cliff. The railings also as someone already said, run parallel to the city from where you start off. they’re on a bridge over your head. the following are some pictures i just quickly snapped
this is the end of the map in EP1 where the explosion hits note the distance from the citadel, you’re still pretty damn close.
this is where you start in EP2 again note the distance, you’re pretty damn far away now.
meaning you either got blown off the tracks and flailed into the distance (not likely because you fell through the tracks most likely because they’re old and have not been used in years and they just got hit with a shock wave at the end of ep1 that probably caused a great deal of structural damage. or you blacked out and the train kept going until it hit this failing segment of the train tracks, again i would like to reiterate that we have no clue how long we were out. Sorry for the long post.