Hot.

I attended the Arts on Fire Fest over the weekend and got to see the Ring of Fire! I'm not really someone into trains or railroads, other than for the visual delights, and the Ring of Fire was certainly a delight! And I did learn something:

'There are hundreds of parts of a steam locomotive that wear out - wheels included. In order to replace the wearing parts of wheels, a tire is applied to the locomotive over the locomotive wheel. Replacing this tire is much less expensive than replacing the whole wheel. The tires are held in place by shrinking them onto the wheel. The tire is machined so that the inside diameter is slightly smaller than the wheels outside diameter. Then, the tire is heated with a "ring of fire"- a series of ignited gas jets. In a short time, the tire is heated to about 350 degrees Fahrenheit. This expands the tire enough so that it fits over the wheel. Once the tire is in place on the wheel, the heat is removed. The tire cools and shrinks, providing a tight joint between the two that is strong enough for regular service on the railroad.'" - from the Steamtown NPS website.

The event is held at the Scranton Iron Furnaces, another visual delight - and one I have yet to get a good photo of...but I can keep trying  :)