Steam Locomotive Appliances

Okay, you just bought your first steam locomotive for your layout. There are all kinds of bumps and pipes on the boiler, but do you have any idea as to what they accomplished? This clinic is designed to inform the modeler as to their identification, purpose, historical advancements, and improvements to locomotive thermal efficiency and safety. All in the interest of avoiding embarrassing mistakes, making better/more accurate models, and encouraging scratch-building and kit bashing.