Lego bricks are not only for cars and aircraft, one can make locomotives as well. Just like Tony Sava does it. He introduced his newest creation, the Chesapeake & Ohio H8 Allegheny class locomotive that is the biggest locomotive ever made. Its empty weight is no less than 328 tons and fully prepared it can weight more than 480 tons!
His creations include smaller locomotives like this American Standard engine that can be bought by $135 in the Bricklink store:
More locomotives from Tony Sava here.