Given that you had to deliberately ignore the extremely obvious spoiler block on what I meant by "disruptive" to come to this conclusion, I can only conclude that you are arguing in bad faith, and know you're doing so and know that you're deliberately using a bad, incorrect, uncommon, and ultimately useless definition of "normal railroad game."
That said, I am a sucker, so I'll bite the bait one more time.
No.
1. Railroad game: Where the plot has specific roles the PCs are to fill, and requires the PCs to play particular ways and take particular paths for the plot to advance, lest it break down and be "disrupted" in a way that makes the DM unable to progress.
2. Sandbox game: Where the "plot" is a combination of stuff that's happening if the PCs don't intervene, and the PCs' interventions causing those events to alter.
The difference is that a sandbox doesn't have a pre-scripted part for the PCs to play. When the PCs "choose a plot" (as you keep trying to put it), they aren't jumping into gaping holes in the narrative and filling them, riding along the DM's pre-scripted path. Instead, they're seeing something that the DM has going on, and getting involved. Their involvement changes how it goes, according to how they involve themselves. The DM has not created a role for them to fill, nor a series of events which are the pre-scripted result of PC actions. Instead, he has the NPCs and environment react to the PCs' actions, altering the outcomes of what would have happened if the PCs weren't there.