All the carriages on the train are suddenly filled from end-to-end with an ever-expanding Wahbah as they bulge and deform around the djinn's body and her seemingly endless tail. The accelerated growth should come to an end in a moment though once a few doors pop out of their frames to open up some space.
Or they can enter a tunnel at the most inconvenient of times - one of the two.
This is page four of a comic commission for VDO featuring their character, Wahbah.