How does one distinguish between the steam dome, and the sand dome on a steam locomotive. What about larger locomotives with more than two domes, what are the extra ones for? I appreciate all the wonderful help you have all been giving me.
Dave
Steam domes frequently (but not always) have the whistle mounted on them. They are always circular in horizontal cross-section, since they have to contain full boiler pressure.
Sand domes always have large covers (for filling.) Quite frequently, the sand piping is visible, sloping away to the front and rear of the drivers.
If a locomotive only has one dome, it is almost certainly the steam dome or a combined casing where the sand boxes and steam dome are under a common outer cover, a very usual Japanese practice also found on D&H 4-6-2’s.
If a locomotive has three domes, two are sand domes. On switchers, articulateds and turn-of-the-(20th) century tank locos, the sand domes are front and back, with the steam dome in the center. On some Santa Fe road locos operating over heavily-graded divisions, there were two big sand domes forward of the steam dome.
For all steam locomotives, servicing sand was almost as important as servicing fuel and water. For diesels, water is less important. For electrics, sand is the only consumable item regularly serviced.
Chuck (who would love to figure out how to model working sanders in HOj.)
Making the sanders work is easy, it’s getting the HO scale sand, that’s the hard part.
[:D][;)]
It should be pointed out that on some modern steam locomotives, the steam dome is reduced to a small flat blister near the cab.
Safety valves were often, if not always, installed on top of the steam domes. Sand domes are also usually larger than the steam domes.
Sand domes, if there are only two domes on the engine, are most often the forward of the two, and are smooth contoured with a hatch for filling. As stated above, tubes run from the sand dome down to the drivers, usually at an angle. Most often (not always) the sand dome is also the larger of the two. Some Hudsons (Lackawanna RR) had weird, large sand domes that were flared wide at the top, and tapered toward the boiler for extra capacity.
I have a question that is related to this thread so I will borrow the readers for a moment and possibly get an answer. I don’t really know the mechanics of the sanding system. Maybe someone could straighten me out on this. I understand the sand is dribbled out onto the wheels??? to give it traction? If this is true then why is there not three inches of used sand covering the ballast along the track particularly on a grade??? Does the sand disentigrate? Thanks in advance always been wondering about this.
Terry[8D]
A friend of mine who sometimes fires on the Smoky Mountain Scenic RR says they usually trickle a small stream of water on the rails behind the drivers to wa***he sand off the rails. Less wear and tear on the running gear of the tender and cars. The used sand I supposed would wash down into the ballast and at some point would eventually build up to the rails. I guess the only reason there’s not so much sand is track maintenance (replacing ties). Southern Railway even had a special train that would scoop out the ballast next to the track, shake and sift the small stuff out of the ballast, and drop the “clean” gravel back next to the track. The dirt and trash would be dropped into an adjacent hopper or gon, and (presumably) used for fill at some point.
The sanding system itself works on the same principle as a gravity feed sandblasting system. Pressurized air going out the sand delivery pipe creates a suction on the bottom of the sandbox, drawing a small stream of sand with it (also like a siphon feed airbrush). You don’t need much sand, a little goes a long way. The sand is actually blown, not on top of the wheels, but just in front of them and is blown almost underneath.
Brad
Dry sand can be gravity fed from the (warm if not hot) sand dome on top of the boile
Asking where the sand goes is like asking today where all the rubber that wears off of automobile and trucks goes along the highways. It’s there but it’s so dispersed that you will never see a pile of it.
Thank you for the info. It clears it up for me and I apologize Dave for highjacking your thread.
Terry[8D]
Not only is it there, but it is most emphatically in evidence on lines which handle heavy tonnage upgrade. I have seen numerous photos of N&W right-of-way where the upgrade track was so sand-fouled that the tie plates were buried. Cleaning sand out of the ballast bed is a major MW problem, so much so that when an SP employee came up with a new sander that reduced sand consumption by 90-95 percent it made the rail industry equivalent of natiional news.
Chuck