Big Boy Inside Out Poster

Exclusively from Trains magazine, take a look inside Big Boy, an over-the-top bit of rolling genius. This cutaway drawing lets you follow coal and water as they're converted to 300 psi steam that is used to move four sets of pistons to drive 16 68-inch-diameter Boxpok-type drivers. This poster is 24" x 11" and is printed on 100 lb gloss text stock.  Ships folded and flat.