Trains certainly seem to be a popular topic for the children we see in our autism clinic. I see several probable reasons for the wide appeal among individuals on the autism spectrum – regardless of their ages. First, trains have wheels, and this will appeal to those whose sensory interests include watching objects spin. This is certainly common among children with autism. In fact, spending an extraordinary amount of time spinning and rotating toys is among the signs that a toddler may be at increased risk of going on to be develop autism spectrum disorder (ASD). Second, trains can be categorized into different models, types, sizes, etc.
Read more here.