Hi Folks, First time user and very new to trains.
Question: What is sand used for?
One of the reasons trains are very efficient is the use of steel wheels on steel rails. It is possible to move a car by hand in some instances since the total area of contact can be a small a 1/4" per wheel. Unlike tires on asphalt or concrete it is very easy for a locomotive wheel set to break free and spin during high loads such as starting or climbing steep grades. Sand is used to increase adhesion in those instances preventing wheel slip in most cases. there have been instances of trains in tunnels unaware they are standing still and the wheels are slipping. The heat generated has melted rails causing the locomotive to be unmovable without a great deal of work and limited area to resolve the problem.
Wow! I never would have figured that out. Seems quite simple and understandable now.
New Question? Where is the sand stored and how is it dispenced to the wheels on the engines? Did steam locos use this method too?
linmark,
Both steam and diesel locomotives use sand for traction, as described by Norm. In steam locomotives, the sand is stored in the front portion of the locomotive in an area known as the sand dome.
(Click on pic for enlargement)
If you look at a steamer (like the 2-8-2 Mikado pictured above), there are always two rounded domes that protrude up. The front (in the case, the larger) one is the sand dome; the rear (and slightly taller and smaller) one is the steam dome.
The reason for the sand being stored here is two fold:
- It’s next to the boiler and thereby keeps the sand dry. (VERY important, as you will see why in reason #2.)
- The small tube for dispensing the sand can easily be located right in front of the driver wheels - i.e. the largest ones that supply all the raw power to the train.
Like the sand inside an hour glass, the sand used in a locomotive MUST be dry so that it can flow easily and not clog up inside the tube. Steam (and diesel) locomotives have a valve inside the cab area that the engineer can open and close in order to dispense sand to the drivers. Sand is used either at start up (when the locomotive is beginning to pull the train and needs the additional traction), or when going up a hill or grade (to keep the locomotive from slipping backwards). Although a diesel locomotive runs differently than a steam locomotive, sand is still stored and dispensed much the same way.
linmark, sand was located in the fueling and servicing areas of all railroad yards. Here is where the locomotives received their water, sand, coal, had their ash pans emptied, undersides inspected, and were lubricated, cleaned and/or repaired, if needed. Steam locomotives were always higher maintenance than their diesel counterpart, which eventually led to the dieselization of the railroads and the demise of steam engine. (But, steam engine are sure a
Sand is used by all types of locomotives, steam, diesel and electric. Once you get used to the characteristics, it will be easy to spot the sand boxes, since they are always above the drivers and have fairly large covered openings for filling.
One seldom-considered use of sand was for cleaning the flues of oil burning steam locos. The low-grade oil burned in steam locos would deposit a layer of soot in the flues, impeding both heat transfer and the free flow of combustion gases through the boiler. When the loco was steaming hard (and developing maximum draft) the fireman would hold a scoopful of sand at the partially-open firebox door, allowing it to be sucked into the firebox and through the flues. The resultant black cloud would send birds to roost at noon.
Chuck
Thanks, Chuck! I’m always learnin’ sumpin’ new about railroading. [:)]
Tom
Tom,
That was an excellent article you wrote. I learnt from it, so thanks. You were writing about US practice no doubt. In other parts of the world there was not always a sand dome on top of the boiler.
One example in the photos is a 19th century design, but a few of the class did continue in service until the sad day when the last steam engine ran. See the box above the middle coupled driver? I THINK that is for sand.
The other one is a relatively modern loco introduced in the 1950s, when diesels were already coming into service. I suppose the railway men of the time did not want to rely on diesels altogether.
Probably the reason they did not put a sand dome on this one is that the boiler was a long way from either set of driving wheels.
The photo shows a pre-production model and what I think are the sand boxes have not yet been painted.
Just an addition - not a correction.
I am awaiting my model of this fella. About July I hope.
John,
Yes, I was strictly referring to American steamers and diesels. Wow! That’s quite the unusual (for me) steamer you have pictured there, John. You mentioned that the second to the last pic is a pre-production model and that you are awaiting it’s arrival. What’s the name of that particular locomotive and which manufacturere is coming out with it? Thanks.
Tom
Tom and Chuck have said it better than I ever could have – Traction is what it’s all about.
All,
I can’t thank you enough for the info. It is truely amazing, the knowlege that is passed along in these forums. I’ve been into RC Airplanes for 15 plus years. I can’t remember a time when so much was given so freely. This is going to be a great additional hobby to be involved in. Again, I say thank you.
The “strange” looking engine is a Beyer Garret. Very big in 3d world RRs because they could put out the tractive effort of an articulated but were sufficiently flexible for tight curves and uneven track. South Africa, I think, was the biggest user.
linmark,
You haven’t gotten my bill yet. [:)]
Jim,
Thanks for the info on the unusual looking steamer.
Tom
Beyer Garratt., after the designer, Herbert W. Garratt. The engine pictured is a New South Wales Government Railway AD60 class. I got my introduction to mechanical stoker firing on one of these engines, 6029. The AD60s were very well liked by engineman - they were fast, rode very well, and steamed like a witch. The running shed fitters and boilermakers liked them too, as they were much easier to maintain than the collection of ancient kettles that preceded them.
As Jim notes, Garratts were very popular in South Africa, but they were common on railways throughout Africa, and the rest of the world. The only place they were never used is North America. And they weren’t just “light lines” power for developing countries - the Spanish and Algerian examples were fast heavy passenger engines.
Cheers,
Mark.
(Garratt gunzel, as you’ve probably guessed [:D] )
One other thing to mention is right behind a driving axle would normally be the rail-washers to wash the sand off the rails so the train doesn’t have to run thru all of the sand. Generally, only the last engine would “wash” the rails.
Someobdy else can go deeper into the subject.
dingoix…I believe your refering to the rear or reverse sanders… There is a sand nozzel at the front as well as the back of the wheel set, Perhaps what your refering to is a rock guard, a small plate or rubber flap, It does look like a wiper come to think about it.
furthering todays class Sanders 101…into the 80s…LOL.
To operate the sanders by hand, the air valve handle can be pushed forward or backward, depending on which way your going so the proper leading sander will operate. Can also be air or electricaly activated.by a valve called a sander relay, releasing air pressure blowing sand out of the sand box down the line to the wheel set…Just like a sand blaster would, but just a trickle of sand.
I only know diesel locomotives, when MUed togather, the sander hose is one of the three hoses on each corner of a frieght unit, passengers have four hoses (signal control hose).
The sanders can be actuated in different ways,
If a wheel slip light come’s on they automaticaly activate, for traction
Engeener may feel the need and apply sand due to his experience, increased traction powering up, pulling grades ect
Emergency braking, if he throws the automatic brake valve lever into emergency, or if a brake pipe (main train line hose) fails, quickley dumping air pressure in the train, the brakes set up and the sanders activate. increasing brakeing effort and reduceing wheel slip
The locomotive inspector will operate the brake valves through various applications, before releaseing the unit from the shops ready track (outbound lead), the last check was an emergency application setting up all the units MUed brakes and a visual was performed noting that all sander functioned
If a sander is not operating and the wheel spins, the tread can become in a since molted, tread will have a spalling or rippling effect, this is glass hard when turning the degfective wheel on
I saw a Beyer Garrett working in Zimbabwe in 1980. It was like seeing a brontosaurus – startling both in its size and the fact that it was so unexpected.
The Locomotive that he was waiting for is a Beyer (Peacock) Garratt. These locomotives have two sets of driver seperated by the boiler. The boiler sits on a frame between the two drivers. They are very unique locomotives.
Very unique? I wasn’t aware there were degrees of uniqueness. But at any rate, there are other articulated designs that also fit your description…so they aren’t unique at all. Cheers, Mark.
Tom,
Sorry, just read your post. The reply is a bit late.
As Mark wrote it is a Garratt AD60 class NSWGR. A pair of them actually. That’s some wheels! 4-8-4+4-8-4 & 4-8-4+4-8-4.
To answer your question Google “Eureka Models”. or http://eurekamodels.com.au/