Not to derail the thread but if you could make these puppies you'd be golden:
http://www.cnn.com/2005/TRAVEL/04/21/amtrak.acela.ap/index.html?section=cnn_latest
"Amtrak pulled all of its 20 Acela trains out of service on Friday after finding millimeter-size cracks in 300 of the fleet's 1,440 disc brake rotors. Each Acela train has 72 brakes.
"This part is unique to the Acela and there is no active production line casting them," said Crosbie said. "The manufacturer has told me this will take some time."
Crosbie said there are fewer than 70 disc brakes available now."