No, GTA 5's Train *Can't* Be Stopped
If you've been paying attention to the GTA 5 YouTube sphere, you may have noticed a slew of videos following a "can X stop the train" trend. You might have also noticed that about 95% of said videos are trash with zero production value, with the remaining 5% being videos parodying and critiquing the new trend.
Now, it's pretty clear that even the people making these bloody things are quite aware that the train in GTA 5 cannot be stopped through any conventional method, however in order to possibly stop or at the very least slow down the creation of such videos, one game developer has taken to Reddit in order to explain just why the train cannot be stopped through any external force whatsoever.
Now, I can already hear furious little fingers tapping on keyboards, so let me stop you there: yes, we know that there is a station on the map's eastern side where the train stops for circa half a minute, allowing players to board. Killing the railroad engineer driving the thing will prevent it from leaving until it despawns and respawns.
However once the train is tearing through the countryside and rolling about to its merry, there is no way a player may stop it, be it through conventional means or through the use of trainers to spawn in props and objects. In fact, you'd need to dig into the code of the game in order to get the train to stop, and now that's just cheating.
Those of you who have some experience in game development will probably have already figured this out, and don't need any kind of explanation. That said, the vast majority of people who play video games know next to nothing about how they're made, so this is mostly intended for that audience.
Basically, when it comes to in-game assets and objects, items are either static or dynamic, usually. Dynamic objects are tied to the physics engine, and react to external stimuli, such as clipping, collision, movement and such. Dynamic objects in GTA 5 include vehicles, NPCs and you — meaning the player character.
Then you have static objects. Static objects are generally those assets which remain exactly the same, all the time. No external effect alters their appearance or position, beyond possibly triggering the texture for bullet-holes or particle effects and such. In GTA 5, static objects include things like the buildings, the map itself and trees.
And the train. The train in GTA 5 is a static object, hence being unstoppable. But why? Well, that's where mrgame64's explanation comes into play. The reason you can't stop the train with other dynamic objects, like vehicles, NPCs and weapons fire is because dynamic objects have no effect on static ones. That said, static objects do have an effect on dynamic ones, hence the train pushing everything away in its path. And killing you.
As for the reason why you can't stop the train by spawning in other static objects, like trees, is also pretty simple. Static objects are programmed to have an effect on dynamic ones, however, being static, no form of unprecedented interaction between static objects occurs during regular gameplay. Hence, there is no collision between static objects, and the train will simply clip through the trees or whatever it is you put in front of it.
However, don't mistake static objects as immovable as a rule. While static objects typically don't move, there is nothing preventing their x/y/z coordinates from being altered cyclically. Hence, the movement of the train along the tracks occurs independently of the physics engine, which is why no force that would under realistic physical circumstances slow or stop the train actually does anything to it.
As such, the train can technically only be stopped if you dig into GTA 5's code, and prevent the x/y/z coordinates from being rewritten, thus making the train unmoving, causing it to remain in the same location as it spawns.
So there you have it. All of these train stopping GTA 5 videos are pointless, and even if the concept had some potential for humor and entertainment at one point, the fact that they have been done to death removes any amusing quality of it. You can't force a meme, after all.
Have you ever attempted to stop GTA 5's train in some manner?