Manufactured from good old E Coli. That means that the new fragrance could be called Eau de Colon

Looks like there are two trains.
As the first enters the tunnel, it immediately diverts underneath the table and continues in a loop.
Meanwhile, a second train which has been hiding in motion underneath, emerges from it's loop from under the table at the exit of the tunnel to appear as if train #1 has disappeared.
And so on...