I post this question not to draw attention to anyone's error, but only as to further my understanding of this art.

I know black exhaust is caused from a rich fire, not enough oxygen and too much fuel.

What causes white exhaust smoke? Not steam.
In this picture, could the fire have possibly been sucked out?


adofmsu@aol.com

> What causes white exhaust smoke? Not steam.
> In this picture, could the fire have
> possibly been sucked out?

Not sucked out, but possibly went out momentarily, which can be caused by a number of things, such as cutting back the firing valve a tad too far, which can cause the fire to go out for a second or so, or a slug of bad fuel oil.

Or cutting back the fire deliberately, say, to avoid the pops opening.

A high relative humity for a given tenperature can cause any steam to show white. Water making its way to the cylinders due to foaming or primming can cause a white stack as well.


EPSW271@aol.com

I would guess that white smoke would be more commonly seen with wood or oil fired engines than coal. Although a condensate cloud on a cold day would account for it too.

Now, if you really wanted to chase away the photographers, you simply need to get some of that "glorified western Pennsylvania slate". You'll make a totally noxious, unphotogenic greenish-brown smoke that just hangs.

During one of the double headed photo runs on the GCRY with GCRY 4960 and ATSF 3751 last Aug., The 4960 was being forced fired for black smoke effect. The engine was being worked hard (I imagine close to or at full throttle)and white steam was also emitting from the stack at the same time. I don't know if the engine was foaming or not, but it made for some great photos. Could just working the engine extreemly hard cause this as well?

edwinsinclair@hotmail.com

> I post this question not to draw attention
> to anyone's error, but only as to further my
> understanding of this art.

> I know black exhaust is caused from a rich
> fire, not enough oxygen and too much fuel.

> What causes white exhaust smoke? Not steam.
> In this picture, could the fire have
> possibly been sucked out?

I am not sure of this location but what you are probably seeing is a temporary 'Gassing', a white or yellowish smoke. This caused by too much air for the amount of fuel. I doubt if the fire was out.
If it is the location I am thinking, the train had just crested the summit and the fireman was tring to recover from the change of profile, going down rather than up which changes the water level in the sight glass considerably, and the change in draft from the sharp exhaust of pulling up hill to drifting downward with little exhaust. With the SP&S 700, it is much easier to fire going uphill rather than down.


vander700@cs.com

> During one of the double headed photo runs
> on the GCRY with GCRY 4960 and ATSF 3751
> last Aug., The 4960 was being forced fired
> for black smoke effect. The engine was being
> worked hard (I imagine close to or at full
> throttle)and white steam was also emitting
> from the stack at the same time. I don't
> know if the engine was foaming or not, but
> it made for some great photos. Could just
> working the engine extreemly hard cause this
> as well?

They worked water. The fireman that day on 4960 is very talented but he had not been out in a while. He told me they worked water at a photo runby on Apex grade. He did not enjoy the water fountain.


EPSW271@aol.com

> They worked water. The fireman that day on
> 4960 is very talented but he had not been
> out in a while. He told me they worked water
> at a photo runby on Apex grade. He did not
> enjoy the water fountain.

Been there, done that, ruined the t-shirt.... and NOBODY likes 'black rain', (basic quick primer for those new fellows or them who don't play with steam) when an engine "primes", whether due to high or foamy water, it gets liquid water in the steam line with the steam, which then goes through the cylinders and up the stack--it also washes the lubrication off the cylinder walls, and picks up a lot of soot from the smoke on its journey, and then it precipitates back down out of the air, and deposits it all on your brand new trip shirt...I've found NOTHING that takes it out, either.