Vanishing train defies space and time

It’s a model train like no other: when it enters a tunnel, it seems to defy the properties of space and time. But of course, what you’re seeing is just an illusion. Do you know what the trick involves?

Doesn’t seem like there’s enough space to have a curved and slanted track, but that may be because one thinks it needs to be carried out within a small space. The train takes almost as much time to emerge from the tunnel as to go around the track, so I don’t think it’s a perspective illusion of the tunnel being longer than it appears. My guess is that there’s a second track below the table. The train enters, veers right and down slightly and follows a large loop below the table, re-emerging inside the tunnel.