Anybody know of any tricks to keep the inside of a sand dome dry? From my experience, condensate collects on the interior, and drips down to the sand on a gravity dropped sander. The resulting clumps of sand clog up the lines. In the fall when the rails are leafy and dewy, having reliable sand is nice.
I've seen blocks of wood lining the interior of a Plymouth sand dome. Is that a trick? Why would there be wood in a sand dome?

Insulation, I suspect. Wood is a reasonably decent insulator; in a sand dome, it would hold up better than a softer type of block insulation (like typical steam loco boiler lagging). Insulate the steel and that helps cut down on the condensation forming inside the thing.

Howard P.

I don't know how popular they were, but the 1925 'Cyc. has a mention of electric sandbox heaters. I don't remember who made them and the book is on my desk at work; I'll try and post the manufacturers name tomorrow.

I doubt that they were very common; a turbogenerator can only put out so many watts. I remember reading that some of the NKP Berks had four (4) turbos; 1 each for lighting, ATC, radio and Mars light. Interesting concept, though-

Actually what Jim Baker said is about all that you can do. Mix the sand well before steaming up and rattle the sand delivery pipes with a hard rubber mallet to insure the flow. Live with it but deal with it.

In thinking about this perhaps some type of water protected vent would work. Something to let the humid air out and keep the rain water from coming in.

bk

We had the same problem when we were running our SP 10-wheeler. Heat from the boiler would drive off moisture in the sand. The moisture would then condense at the top of the dome, drip down, and form clumps. We tried that during the time when the engine was warming up and just standing, we took the lid off of the sand dome. That allowed the water vapor to get out, rather than to condense inside the dome. Seemed to help. Of course, here in the San Diego area, the outside temperatures aren't quite as cold as Michigan in the winter, and we aren't as humid in the summer. But it is simple enough to be worth a try. Of course, the drier the sand is when you put it in the dome, the less of a problem you'll have.

Has anyone tried using a bag of dessicant hung in the sandbox and see if that will absorb the moisture?

Sandblast media has worked well for me in the past. If you are buying generic type play sand it will contain some clay like particles which will retain a lot of moisture, which can be driven off and could possibly form condensation later on. Also, those clay like particles will form a cement like substance in the sand dome from the vibrations of the locomotive, more common on diesels than steamers. It helps to keep the dome full, much like keeping your gas tank on your automobile full to keep the condensate out.

Mike Tillger

That heater mentioned above was the "Universal Electric Sand Pipe Heater" from the United States Metallic Packing Company. It consisted of a resistance coil, in the pipe between the sand dome and the sander valve. Again, I'm sure it put quite an added load on the turbos of the day, but with todays diesel technotoasters and all their watts to spare, so what? Might not be a bad idea, if not in use already-

These are all great and helpful hints! My experience is with normal bagged sand and usually only one or two 90 lb. bags in the dome. Perhaps that is why clumps up. I'd like to try that sandblasting media trick.

A smaller breather pipe with an upside-down "U" at the top (made with two street elbows) near the top of the dome will help exhaust water vapor.

When the engine is in steam: Omitting the lagging under the dome gives it steam heat. If extra heat was needed, a loop of copper tubing with steam flowing through would dry the sand dome much more economically than an electric heater run by the turbogenerator. (Steam locomotive turbogenerators are designed for rugged reliability, not efficiency.)

An electric heater would be great in the shop for layup periods with no steam. A rough-service light bulb in a standard "drop light" might be adequate.

- Doug Debs

Has anyone tried to use the material sold for Trackmobile use? It is sold under the name "Trakite" I believe. The grains are fairly large as compared to sand and it doesn't clog up with water the way even sandblasting sand would. No idea what the material really is, I understand it might be expensive.

David Farlow

What Doug says is true, removing the insulation below the dome will help out when done in conjunction with the vent pipe. Also, the use of a large grain blasting media is essential! 20/40 or 12/40 needs to be used, a bit of home work is required in that many suppliers have become sloppy in allowing a good deal fines into the bags...these also cause cloged pipes.

After a trial on both steam locomotives at Greenfield Village this past summer, it turns out that blasting media works perfectly! It doesn't clump in the dome nor the pipes like the sand did.

Try using triple O sandblasting sand. For as little sand as you are using it should not drive up the overall cost of operation. It comes super dry and as long as you don't get it wet you should never have a problem.

Has anyone tried `Black Beauty' otherwise known as ground slag, which is also used for sand blasting? IIRC the stuff does not absorb water since it is mainly mineral glass and other impurities from smelting the steel.

Just an idea

Rich C.