Each row on the carriages has room for 4 word cards, and there are 2 different carriage sizes. The 3-storey carriages have room for 12 words, and the 2-storey carriages have room for 8.
Start with the small carriages, and when your child can read more than 12 Sight Words, you can add the larger carriages to the train. Mix and match carriage sizes as you like.
Find it on the Activities Page under "All Aboard!"