This is a topic that is a source of constant discussion and differing opinions.
For the purposes of this page, I'll address track powered situations only.
There are basically two different things that affect running trains:
Dirt, oil, bugs, etc. This is physical contamination or obstructions.
Oxidation or corrosion that affects the electrical conductivity between the rail and the wheels/pickups on the cars.
Both will interfere with power pickup.
Dirt and physical obstructions:
Dust, dirt, pollen - other dry material
Most of these things can be swept away. You do not need anything abrasive. (In general you want to avoid abrasives, they can put scratches in the rail that help trap dirt and grit)
Track power can often make a fine carbon "dust" on different rail types, and it's different for everyone. I believe it has to do with a lot of factors, current draw, type of metal on the wheels, length of trains. No one has satisfactorily characterized this in my opinion, but I've seen the dust and many people have reported it. I think the electrical arcing of currents helps produce some kind of carbon or oxide "dust".
Also, plastic wheels have been known to abrade to a fine dust also, and also when hot the dust has combined with other factors to adhere more firmly.
In most cases these two above are usually easy to remove.
You can often also wash these containments off with a hose.
Leaves and larger items might need a broom, or a sweeper car: Click here
To clean these types of items, you can use a track cleaner that has a cloth or something like ScotchBrite (like the green scrubber on your kitchen sponge)
You can also use solvent-based cleaners, but you do not need to be careful of leaving a film behind.
Gooey dirt, bugs, etc:
Dead bugs, tree sap, snails, etc, are a bit tougher.
I've had success with a track cleaning car with ScotchBrite, since the open weave will help "collect" the junk, not smear it around.
"eraser" type cleaners will just clog, they are not a good solution.
Bad tree sap might need a solvent. If you use solvent cleaners, be careful you do not use something that will attack the plastic ties. I would recommend alcohol. Not that it is a big deal, but rubbing alcohol has a bit of glycerin in it, so pure methyl alcohol is better.
As above, fine dust from electrical current and/or plastic wheels can combine with moisture, oil, track cleaning fluids, bug sprays, mildew sprays, and sap to make something that is harder to remove. Solvent is usually the best way to get rid of it.
In the smaller scales, it's very important to finish a cleaning with a solvent. If you get a lot of dirt, or gunk on your rails, look to do "wet cleaning".
Oxidation and/or Corrosion:
This is normally the big bugaboo. It is most prevalent on brass track, but can affect almost any metal track given the right (or wrong) conditions.
Oxidation is caused by the oxygen in the air combining with the metal to form a new compound. Normally oxides are an insulator. Pollutants in the air can cause this process to happen faster.
One way to remove oxide is mechanically. You actually scrape the surface off to reveal "new" metal. In the smaller scales, a rubberized compound is typically used. You may remember the "Brite Boy" block. Most of these are a mix of rubber and an abrasive like silicon carbide. See the brand name "Cratex" for this.
The stuff comes in many shapes. You can put it on a sanding block, like the LGB hand block.
There are companies that make track cleaning cars (like Aztec) with rollers of this material.
This stuff is a relatively mild abrasive, so it may take several passes around the layout, but will not leave big scratches in the rail head, or excessively wear the rails.
Another way is to use something much more abrasive, like the open mesh "drywall sandpaper" which looks like window screen with silicon carbide on it. This will "clean" rail very fast, but it will remove a lot of material, and in my opinion, scratches the rail, and the scratches help cause oxide to form more rapidly.
Who makes what, and my opinion: (in alphabetical order)
AristoCraft:
Aristo makes a track cleaning car, it is a bobber caboose with the cupola off. It has a weighted block underneath. The surface looked like masonite/hardboard at first glance. I now understand that mine was packed with goo, and it's a rubberized compound like cratex
It does not clean quickly, and has very low abrasion. You need to clean the block because it tends to smear gunk on the rails when it gets dirty. Soapy water is recommended.
Some people claim to clean it (quickly) with Goo Gone. Solvents will break the block down. Do not use aggressive solvents on it.
Not a bad choice for general, everyday use if kept clean. It is one solid block, so does not do well with track magnets.
I have one. I don't like it because is smears anything greasy like oil or ants.
You can see the block below, and it is on the standard 2 axle chassis.
Aztec:
Aztec (www.aztectrains.com) makes some of the best track cleaning systems in the smaller scales. They recently made a unit in large scale, often in a shorty Aristo box car. They have a roller in a beautifully machined and hard anodized holder. There is also a magnet in it. The roller is not exactly perpendicular to the rails, so there is a light scrubbing effect as well as the constant rolling of the unit. You can also get them to custom make a roller with canvas for you if you wanted to "wet clean" your rails.
Very high quality, probably cannot be used on track with a bunch of dirt and leaves. Should do a great job, I will report back, just bought one in early 2008.
One disadvantage, you have to unscrew the unit from the car to remove the block with the roller, and then unscrew a side plate.
(Aztec notes: to replace canvas on roller, put it in lacquer thinner or acetone, that will loosen the cement. Use contact cement to apply the new canvas. Clean the roller with a tooth brush and warm soapy water, let air dry)
Bridge-Masters:
This is a metal framed car with a free floating block that you can clamp a piece of ScotchBrite on, or even drywall sandpaper. I like it and it is the primary cleaning car I use.
It will go over Kadee magnets. I added more weight to mine, the frame is pretty light. I wish they would sell it set up for couplers on each end. Link to their site
See the picture below for how I added a couple of fishing weights. The frame is so light that when it hits obstructions, it jumps up in the air, the weights help here, and also help keep it on the track if you are pulling it with a body mount coupler on a long wheelbase loco.
Centerline:
Nicely built with a large heavy brass frame with free floating roller:
I like the fact that you can easily remove the roller and clean it, just drops in.
CMX Clean Machine:
I believe this is only distributed through American Hobby Distributors to other dealers. http://www.tonystrains.com/products/cmx-products.htm This unit has a brass tank with 2 weighted cleaning pads, and the cleaning liquid can be metered from the tank to wet the 2 pads. I have not used one of these, but they look very well built. This unit can do wet cleaning or dry cleaning. You can put different pads on the system. Basically you can do whatever you want.
The only shortcoming would be that the pads are small, thus could load up with gunk more readily, also the center of the pads are not cut out, so it will definitely bump over magnets and switches. It would be nice to be able to control the solvent flow to only one of the 2 pads, but this is a icing on the cake request.
The pads look relatively easy to change.
I would say this is probably the ultimate cleaner, but it comes with an ultimate price: $250.
Have not tried it, but it has a foam pad with slits so the foam cleans the backsides of the wheels as well as the treads.
It looks very effective. The original units were just the foam pad for doing rolling stock, but he added the metal plates to power the trucks. It takes power right from the rails.
About $120 for the largest 36" model. I intend to buy one for my locomotives.
MNP (More New Products)
They have a Aristo bobber caboose with 2 motors that spin 1-1/2" felt pads on the rails. The unit seems to pick up grease and light dirt, but not really things like tree sap, and I'm not sure about removing brass oxidation. They do mention in S scale people put brass cleaner on the pads... and they were pleased with the results... I would think that such a cleaning session would use 2 sets of pads each time (4 pads).
About $165 at http://www.mnpinc.com/Home.htm I thought I saw another version by another company where the motors have up and down motion. Replacement pads are $5 for 6 sets (of 2). They get dirty quick. The unit has a small regulator board and can accept DC/AC/DCC up to 24 volts. There's also an Aristo "mu plug" to be able to run from batteries as well as track power (there is a track/battery switch).
The pads apparently have a self stick on them, so changing them seems to be easy.
R&L Lines:
Interesting. Not pretty, but the rollers are inexpensive throwaway paint rollers. Nice inexpensive way to clean rails. You can drip some cleaning fluid on the rollers, not really convenient, but doable. Many good reviews. Wendell Hanks reports that the width of the Track Scrubber car -- with the foam rollers set at the angle received from the manufacturer -- is 4". He guesses that if the rollers were set "straight out" at a 45 degree angle, the car width would be 4 1/2 inches. Both height of the rollers and their angle is adjustable.
$129.99G-Scale with Aristocraft trucks, knuckle or hook and loop couplers or MTH knuckle couplers (includes 4 rollers, cleaning solution not included, $3.99 extra) http://www.rllines.com
Trackman 2000:
Very nice looking unit: http://www.trackman2000.com heavy, and with a synthetic pad that cleans the rails. They are about $135. The cleaning pad is suspended between the 2 trucks with a clever mechanism that keeps it centered over the rails. The cleaning pad block has the center cut out to help get over track magnets and switches.
The cleaning pads are made of something called "Bear-Tex". It is made by Norton, and looks identical to 3m's ScotchBrite, but tougher, and they say it's better and snags and shreds less. The replacement pads are $4.50 per set. It comes with Aristo couplers.
I have not used one, but they look very nice. You can adjust the tension on the pads for a light dusting to a thorough scrubbing. I believe they would work very well, a trifle expensive for most. It does not do wet cleaning.
Apparently the original owner of the company has passed away. I was just contacted in July 2009 that Ludwig Dischner of The Last Train Stop ( http://www.lasttrainstop.com/ ) has purchased the patent and they are currently in production to the same exacting standards.
In the picture below, you can see the mechanism (top bar and 2 shorter bars) that keep the block centered as the trucks swivel:
The picture below shows a closeup of the mechanism, and also of the nylon "buttons" that secure the cleaning pads
Here's the underside, where you can see that the pads only hit the rails, and there is clearance in the center for track magnets, and also so you are not grinding down frogs.
Here's an image of the HO unit until I receive a new picture of the G scale one:
There is a powered roller that turns the wheels by contact with the flanges. This looks very cool for rolling stock, the first unit I have seen that turns the wheels. The unit appears to have a toothed belt and sprocket to provide plenty of torque to turn the wheels.
The price is $70 and seems very reasonable for what it does.
Here's a video demonstrating mine:
Conclusions:
If your priority is money, then buy a pole sander from Home Depot, and put a piece of scotchbrite on it, or the drywall sandpaper if insist on the least effort and don't mind risking the rail surface if you use the sandpaper. Use the Maroon scotchbrite is my suggestion.
If you want something to kind of keep the rails clean and you do not have a severe oxidation or cleaning problem, get the Aristo unit and run it every time you run. Used this way and often, it will keep everything clean for cheap, and just clean the block fairly often with a rag with a mild solvent or with a stiff bristle brush.
If you have a lot of oxidation, or want to clean it faster, get the Aztec or the Trackman2000 or the CMX. Non is cheap, but they will all do a good job. The Aztec rolls over the rails so it can be in a long train, and does not need extra locos.
If you have a bunch of gunk on the track or weird buildup, then I would use a solvent based machine, like the Aztec with a canvas roller, or the CMX or the R&L. You can get the rails squeaky clean.
Remember, if you have gunk on the track, you do not want to just smear it around, it needs to be picked up somehow. Oxidation can be rubbed off with an abrasive.
