As the people on the track are moving at an accelerated speed of 0 m/s, normally a train would apply the full force of the train moving to the ~~meat bags~~ human ethic problems on the tracks.

As newton's first law states F = m*a, or Force = Mass * acceleration

F = x * 0 = 0 N of force

thus, they could just plop out as if falling after having a chair removed.