Many of us have had fun with the double- and triple-time stamping technique (you can see one example here), where you layer graduated sizes of card stock and stamp all of them at once. It’s an excellent technique, and you must try it at least once!
But this card is simpler! Instead of stamping two pieces of card stock for the train, just use one panel (this one of Very Vanilla is 2¾” square). After stamping, use a Square Framelits to die cut a focal point of the image, making sure the edges are parallel to the original panel. Then mat both pieces, and pop up the smaller one, aligning the image and covering the hole in the bigger panel.
It’s not necessary for the smaller piece to be exactly in the middle — it’s actually more interesting (and easier) to have it off-center! Here’s a closer view:
Stamps: Traveler (p. 38), Something to Say (p. 104)
Ink/color: Memento Tuxedo Black
Paper: Very Vanilla, Soft Sky, Basic Gray
Other: Big Shot, Arrows Embossing Folder, Squares Collection Framelits, Stampin’ Dimensionals