Re: Question about Chama

Sam,

I have seen some tourist railroads and museums take a cold, medium-size engine (<100 tons) and bring it up to operating pressure in about 3 hours using shop air for blower. That said, I think that true steam gurus would tell you that regularly bringing your engines up that fast is not a good thing and in the long-run, you may have issues with firebox sheets, staybolts and goodness knows what else. Mechanical engineers have long known that "thermal shocking" or "thermal fatigue" can lead to premature failure of metal parts. The same sort of phenomenon can happen to air-cooled, aircraft piston engines if a careless pilot rapidly throttles back from cruise power to idle....and then initiates a steep descent.

At one (very) prominent tourist railroad in the eastern US, I have observed that they do things much more cautiously. If it is Monday morning, and they know that Engine XXX is needed tomorrow, they will start warming up the engine using a kerosene-fired torpedo heater in the firebox sometime around mid-day today. In the late afternoon or early evening, they will light a wood fire and let that burn for 2-3 hours before they start adding coal. All told their process takes about 12-18 hrs....but is probably a lot easier on the 100+ year old equipment.

Travel around the country and you'll see all kinds of variations. It depends upon the size of the engine, and how careful the owner wants to be with it.

/Kevin