Flue Sanding

[Anonymous]

Was just watching a Pentrex video. An SW switcher was pulling an old Baldwin steamer out of a tight radius siding. Once on the main line, it used it's dynamic braking to provide resistance so the Baldwin could "sand it's flue's". How and why would you sand the flue's and why does it produce so much smoke?

[Randy Stahl]

The sand breaks up the accumulated carbon in the flues. The loose carbon is ejected out the stack if there is enough stack velocity
Randy

[Anonymous]

Normal firing builds up a layer of material on the inside of the flue's that insulates the hot gases from heating the water correctly. When the engine is worked fairly hard, sand is fed into the firebox door opening and it is drafted up into the flues cleaning out everything that is inside on the walls of the flues. This is really dirty stuff and it goes up and out the stack if the engine is pulling hard. That is why the diesel used the dynamics to provide a load on the engine when the flues were sanded. It was done as a matter of course in normal railroading.

[athelney]

On #2860 we have a small bin on the back wall of the cab -- it's filled with a moderatly coarse sand together with a small hand shovel to insert the sand into the firebox. In the video ' At The Throttle ' showing CN 6060 4-8-4 going to the Expo in Vancouver in 1986 there is a whole sequence showing them "sanding the flue's ' as it is pulling the train away from a meet on the CN mainline in the fraser canyon BC

[jchnhtfd]

Aw shucks. And I always thought that the crew sanded the flues specially to put on a show for the railfans...

[CSSHEGEWISCH]

Unless I'm mistaken, sanding the flues is a practice required only of oil-burning steam locomotives. I would think that the fly ash and cinders on coal burners would serve the same purpose as the sand on an oil-burner.

[Randy Stahl]

Not if it's just sitting around smoking. Idle time on any steam locomotive fouls the flues. Need to blast the crap out other wise you can't make steam. Carbon is a good insulator.
Randy

[athelney]

QUOTE: Originally posted by CSSHEGEWISCH

Unless I'm mistaken, sanding the flues is a practice required only of oil-burning steam locomotives. I would think that the fly ash and cinders on coal burners would serve the same purpose as the sand on an oil-burner.

Sanding is normally associated with oil burning locos' -- back in the UK we had mostly coal burners so dropping the gear and cranking the regulator to 2nd valve normally had a similar effect -- unless it started to slip.

[Anonymous]

I have two questions:
1. Why not just let the sand/carbon collect in the ashpan in the smokebox?
2. How often do you need to sand the flues?

Thank you very much in advance for your help.

Sincerely,
Daniel

[Anonymous]

Daniel --

1. In order to scour the carbon from the flues a strong draft is required. That's why the engine is worked hard when sanding flues. The sharp exhaust, which is directed to the stack through the smoke box, increases the draft. Most of the sand and carbon will be ejected through the stack, although some will accumulate at the bottom of the smoke box.

2. Every tour of duty, or more frequently, as conditions require.

--John

[Anonymous]

Dear John,
Thank you very much for clearing that up for me.

Sincerely,
Daniel Parks