Factual error: In the fight scene, where Max is about to kill Blaster after knocking his helmet off, it's discovered that Blaster is mentally disabled, showing signs of him having Down syndrome. A person with this form of disability grows no taller than 5'2". The extra chromosome in their body causes disruptions in their brain growth and health, which causes them to be of a small size their entire lives. Blaster certainly wouldn't be of a tall, large stature as he's depicted in the film with Down syndrome.
Factual error: When Auntie sees Max through the periscope she zooms into him, but the lens is fixed and crude and shows no such zoom feature.
Chosen answer: The train tracks would have been covered by dirt for not being used for years. The truck was already cranked, as the engine was source for the generating power and lights. The exit was boarded up and the truck ripped through it. The kids were not prepared, but did observe what the adults were doing and could have been given instructions on what to do.