I read this; on this forum wheni i first got into model railways and believed it. However yesterday i had reason do something which absolutley belied this. I believe that, after having a slipping Sachsen on a steep slope, i cleaned the rails and lo and behold the traction improved out of sight. So this myth is not true as far as i’m concerned.
What do others think.
Rgds ian
Ian I clean my tracks every week, i only have 175 ft of track out side , i use a scotch brite pad on a sanding block with a handle attached to it , don’t have to get down on my knee’s to clean the tracks. the engines run better when the tracks are cleaned . BEN
maybe dirty wheels improve traction 
(about 2 weeks ago, the Virginia Railway Express, the train I take to work every day, slid right past the station on some leaves. Took 10 minutes to back up b/c needed to get dispatch permission to back up the train–don’t ask me why permission is needed, that’s what the conductor told us, w/out explaining)
I have very unscientificaly noticed that cleaner rails have better traction, but then again I really wasn’t looking in that direction.
Hmmmm… sounds like a good experiment to me…
Clean rails cut my tractive effort in half.
Yeah mate i wasn’rt very scientific either but i agree with you.
Ian
I have no idea… I just run big engines and they pulling anthing you need.
Cleaning rail, dang , I forgot all about that.
We have got some really bright people on this forum!
Ian
I did some research and what I found was that clean rails maximize traction. In fact real railroads spend a huge sum of money researching this very problem. Interestingly wheel slip is used to clean the rails and optimize traction during heavy pulls, along with a shot of sand to help clean the rail of grease and oil. See for yourself:
“……… electrical control systems graduated from slip control to adhesion control. This is because newer control systems were designed that actually allow the wheels to slip slightly, on purpose. It is called creep control. On a heavy pull the wheels will typically by turning a couple of miles an hour faster than the locomotive is moving, and thereby gain the greatest pulling power from the locomotive. You can sometimes hear the effect on a heavy pull when the wheels begin to sing. This means the control system is working hard. The theory is that the slipping wheels will burn off any contamination between the wheels and the rail and thus give a better grip on the rails. With this type of system installed on DC locomotives the adhesion ratings jumped to 25 or 28 percent dispatch adhesion……….”
It stands to reason that dirt on the track could actually lift the wheel off the track, supporting the wheel with dirt particles. Not good for traction.
Oh, just get a bigger engine, bigger is better…hehehehe
You can see the level of interlect on this forum; that was absolutely brilliant Jack and also a very good comment Robert and i have learnt a lot. I am sorry the other comment was so childish and illinformed that i didn’t learn anything from it all.I have tried not to use the word ignorant.
That dissertation Jack was so well informed and i can see in came from a proper research base and of course many of the points they raise are applicable to our hobby; and i have been so impressd i have printed them out and saved them for distribution to associates.
Well done gentlemen
Rgds ian
Don’t thank me, it was your question Ian that made me realize I was ignorant of something that seemed to be important, so I merely corrected my own ignorance by applying information and fact to the problem.
It would seem that for our G scale concerns clean rail and heavier locos are the cure for traction problems. Adding weight to a loco is an art and a voodoo at the same time, we want a heavy loco for traction, but not so heavy it won’t pull the load that it’s intended to. Seems that we must do as the full sized railroads and use the trial and error method to obtain useful results.
If you are running track power, then you MUST clean the track. If you put RCS into the locomotives and then who gives a crap about the track. If you have batteries then you could run the locomotives on the floor (Not always the best idea though). On REAL railroads, yes slightly dirty rails will improve your traction. Heck even the locomtives are making the track dirty by them putting sand on the rail for improved traction.
Interesting counterpoint Do you have experimental data to support, or is it just observation? I am interested in another view point if there is some empirical data to compare.
Of course with track power clean rails are required for conductivity, battery power and live steam who cares, but the topic is on traction. Sand is used by locos to scrub the rails free of ice, oil and other contaminates. It is reasoned that if you can increase the coefficient of friction by 10% or more by artificial means (sand), in effect cleaning the rails by sandblasting. I wonder what track looks like after it was hit by sand and a 100 ton loco runs over it, I expect clean and shiny? How much sand remains on the rail head after being sprayed there under pressure? Surely not enough to help anything but the first set of drive wheels on the loco. What about the other drivers, seems they would not be running on sand, but on the now cleaned rails left behind by the first set of road wheels. The optimum traction happens with molecule to molecule contact from steel rail to steel wheel. The same physics apply to the garden railroad, albeit on a far smaller scale.
For most of our miniature railroads this just is never an issue. It only comes into play when we haul long trains and have steep grades. In these instances adding weight to the loco and cleaning the rails shiny (regardless of power source) WILL increase traction. My money is on the millions of dollars and pounds the railroads have spent on research and specialized equipment to find the answer to traction problems, as well as my own degree in physics which verifies the data presented earlier.
A
IMHO, there is something else at work when it comes to sand on the rails. Back when I lived where there was snow and ice, kitty litter was purchased even though I had no cats; it was kept in the car. When stuck on ice, which is slippery - the essence of clean, a little kitty litter spread in front of and back of the wheels provided the necessary traction to get the car moving. Rather analogous to paint and shiny, polished, really clean surfaces; the surface must have ‘tooth’ for the paint to grab hold of.
I have always thought that the sand textured the rail and produced a non-slip surface. Masons always use sharp sand, not the beach stuff which has been polished by the ocean waves.
Just my two cents. Art
Putting sand on the rails makes for “bite”. It’s not the same as making the rails dirty. THere’s a difference between grit and greasy, oily dirt. The regular buildup that collects on model railroad tracks is usually oily and greasy. Think of it like rain water lifting a tire off the road and causing hydroplaning. Same principle. The dirt on the rails causes the wheels to have less of a contact patch with the rail, and traction diminishes. Now, add JUST grit to the situation, such as sand, and traction improves because of the biting action of the sand. One could actually argue that like sandpaper, the sand helps clean the wheels and rails to also improve traction that way, as well. Have you ever seen rails that were freshly sanded after a train goes by? They are shiny as a mirror, because the sand cleans as well as bites. I’ve heard of using all sorts of compounds to clean and polish rails, but I clean them dry. I don’t want any sort of residue left over from anything. A Bright Boy works well, but I usually just use a standard large flat eraser from wal mart.
Great thread Ian!
Now I am thinking what is the weight of the loco need to be, or is there one?!
And what about modern ones?! Both can/could pull abit of weight if balanced?!
William
True, but ice is slippery not because of the clean ice, but because the pressure of an object (your boot for example) compresses the ice and forms a microscopic film of water between your boot and the ice. The water acts as a lubricant, that is what makes ice slippery. Using kitty litter or sand interferes with the ability of the ice to form the water film, creating a good grip.
As an aside, my surf buddies refer to this as “gription”- used in a sentence: “Dude, I wiped because I lost my gription on the board”
Tangerine-Jack, your points are well taken. You mention in a prior post that the sand is pressure sprayed onto the rail. Having watched a few, it appeared to me that the sand drops onto the rail by gravity.
The effect of the sand does not appear to be long lasting as many engines had two or more sand valves on each side applying sand to more than one driver. Some Santa Fe Mikados had two sand domes with each sand dome having two pipes on each side thereby supplying sand at 4 places on both rails.
I have never checked rails after only the one driver had passed over the sand. Looking at the rails after the entire train has passed is not a satisfactory method of checking the efficacy or the results of sanding.
So I still think grit does it, not shiny clean.
Art