Article: Fine Tuning Athearn Blue Box Locomotives

This is an older article that was published many years ago. I was able to find it in the archives and bring it back as there is a lot of wonderful information to share.

Contents

• Step 1: Removing the Shell
• Step 2: Removing the Trucks
• Step 3: Disassembling the Trucks
• Step 4: Cleaning and Filing the Gears and Wheel-sets
• Step 5: Reassembling and Lubing the Trucks
• Step 6: Reassembling the Locomotive

Step 1: Removing the Shell

The very first step in fine tuning any locomotive of course is to take it apart. The procedure for this will vary depending on the type of Athearn locomotive you own. It’s best to consult the instruction manual which came with your locomotive for instructions on how to remove the shell assembly. However, if you do not have these instructions, follow the steps below:

• Athearn shells with round locating pins below the side sill:
  1. Use a small screw driver to lift the side sill over the locating pins being careful not to break any parts.
  2. Loosen all mounting tabs. GP units have two while SD units have four.
• Athearn shells with no round locating pins below the side sill:
  1. Hold the unit on the sides of the long hood and place your other hand under the fuel tank.
  2. Pinch firmly on the long hood section while pulling gently on the fuel tank.
• It may take some force but be gentle so you don’t break the locating pins.

Step 2: Removing the Trucks

Now that you have the shell removed, you will need to remove one of the trucks. I would suggest removing only one truck at a time as it does make a difference which way the trucks are assembled,  and they will fit back on the wrong way on some units. Also, you can really only work on one truck at a time anyway so why have all the little parts floating around if you don’t have to. The procedure for removing the trucks can be somewhat tricky, but I hope I can get you through it.

1. Remove the metal strip which runs across the top of the motor and out to each truck. Take care not to bend this as this part carries the electrical current from the trucks to the motor. If you prefer to replace this with a wire, refer to the seminar entitled Hard Wiring Athearn Locomotives for more information.
2. It might be easier for you to remove the headlight assembly from the bracket when you need to remove the front truck. This will pull out of the bracket but should be fairly tight. If you will still use this, try not to loosen or break the bracket from the body. It needs to be tight for good electrical contact to the frame. However, if you prefer to replace it, there are many lighting kits available.
3. Locate the plastic cover on the top of the truck. This is the Worm Housing according to the Athearn instructions. You need to remove this piece so that the truck can drop out of the frame. It is the only piece holding the truck to the frame. Before removing this part, place your frame assembly on your work surface and don’t pick it up until you are instructed to do so. If you work out of step, you may lose parts of your worm gear. I find it easiest to use a small screwdriver to remove this part. Place the screwdriver on the frame and gently pry upwards on the part. Be gentle, if you break it, it will not hold the truck on properly after re-assembly.
4. Before removing the truck, you should remove the worm gear and Spline from the assembly being careful not to lose any parts. Each part in this assembly is important, and one missing part can cause your locomotive to run rougher then when we started. Place this assembly in a place where it will not get lost.
5. Now you can safely remove the truck from the frame.

Step 3: Disassembling the Trucks

Now that you have the truck(s) removed from the frame, you will need to disassemble them to get at the gears. Ninety percent of the noise of an Athearn locomotive is caused by flash or loose material in the gear boxes. The next step would be to inspect the gears and insure there are no burs or foreign material on the gears themselves.

1. Before disassembling the trucks, you should remove the side frames and set them aside. These are held on with one or two lugs which snap into the truck. You should only need a little force to remove these, but be gentle and try not to break the lug(s) off. If you wish, you can use a slotted screwdriver to remove these by sliding the screwdriver between the wheel and side frame and twisting.
2. Each truck will have either two or three gear box clips depending on the type of locomotive. The two axle trucks generally have two clips, while the three axle trucks have three. This is the hardest part in disassembling the trucks, so take your time. Gently remove each clip while holding the truck together.

3. I find it best to remove the bottom clip and allow the wheel sets to drop out before removing the top clip(s). This clip can be removed easily by placing the truck upright on your work surface and sliding a screwdriver between the metal wipers and the plastic gear box and pressing down gently. These parts are very brittle and will break with too much force, but should generally come loose easily. When the clip falls free, lift the truck up and set the wheel sets aside.
4. Removing the top clip(s) is a bit more tricky. Do not make the mistake of sticking your screwdriver under the clip and prying up. This can result in breakage or flyaway parts, which we all know are hard to find! Your best bet is to use your screwdriver to gently pry up on one side, then carefully remove the clip with your hand.
5. Now lay the truck on its side and remove the top half to expose the gears. It’s not a big deal if the gears fall out of the truck as you are going to remove them and work on each one individually. Before removing the trucks, make a mental note as to the orientation of the gears for re-assembly later.

Step 4: Cleaning and Filing the Gears and Wheel sets

With the truck now disassembled, you can start to inspect the gears and gear box for burs and foreign material. The inside edges of the gear boxes should be smooth with no burs. You will need to inspect each gear and file away any burs inside the teeth of the gear. This is the most important step in this procedure as burs and foreign material are the number one cause of gear box noise.

1. Inspect each half of the gear box and clean away any burs or debris. Scrub both halves, inside and out, using Isopropyl Alcohol (rubbing alcohol) using a fine brush (a toothbrush works great for this). Use a lint free cloth or paper towel to dry the parts then set them aside to allow them to dry completely.
2. File the inside edges of each gear tooth gently to remove any burs and flash. There is a raised section on the side of the gear to aid in locating your start and end points. You may find it less time consuming to file only the teeth which appear to have burs, but you will get better results if you file each tooth. Even the smallest bur will cause a lot of noise. If find that a triangular shaped needle file is the best tool for this step.
3. After filing all of the gears, use your brush to scrub them with the rubbing alcohol and set them aside to dry. You want to have as much of the alcohol as possible removed from these parts as it will interfere with the lubricating compound which you should apply.
4. Now scrub the gears and wheels of each wheel set with the alcohol. I don’t suggest removing the wheels and filing the gears on the wheel sets as I have never found a problem with these. Set these aside to dry as well.

Step 5: Reassembling and Lubing the Trucks

Once the gear boxes and gears have dried, you can start to reassemble the trucks. This step requires you to have several different types of lubricants. I use the following lubricants from Aero-Car Technology, Inc.:

1. ACT-1111 “NG” Jel Gear Lubricant
2. ACT-3753 Conducta Lube & Cleaner
3. ACT-2002 Motor Bearing Lubricant

Although other brands of lubricants can be used, my descriptions will call for these three products. If you would like to purchase these items, first check your local hobby shop. If you can’t find them there, you can contact the owner in one of the following ways:

1. Snail Mail: P.O. Box 336 Western Springs, IL 60558-0336
2. Phone: (708)246-9027
3. Email

Now that I have all of that out of the way, let me explain how to use these products. The one note I must make regards the product called “NG” Jel. I was told that this product will work equally well in a liquid or solid state, so if yours melts, don’t worry, it will still work. Now, back to the business at hand:

1. Locate the gear box half with the lugs for the gears. Place the gears on the lugs in the same order they were removed. If you don’t remember how they were assembled, follow these basic instructions:
   • Three Axle Trucks: There should be one large gear and four smaller gears. The large gears goes on the lug closest to the worm gear area. The remaining gears (all of which are the same size) go on the remaining lugs.
   • Two Axle Trucks: There should be two large gears and one small gear. The small gear goes on the center lug while the two large gears go on the outer lugs.
   • There may be other configurations for different trucks. If you can’t figure out how to put the gears together, try to locate your instruction sheet, or contact Athearn for a copy.
     
2. After placing all of the gears on their lugs, put a drop of the Motor Bearing Lubricant on each lug. Then, using a toothpick spread some of the “NG” Jel on the gears and manually spin the gears so that all of the teeth are coated.
3. Place the other half of the gear box on the first half and clip the top gear box clip(s) in place.
4. Place the wheel sets into their places on the truck making sure the square nut rides in the square opening in the truck wiper. It would be a good idea to use an NMRA standards gauge to set the gauge of the wheel sets before placing the bottom clip back in place.
5. Use the toothpick to put a bit more “NG” Jel on the exposed gears. Place the truck on a piece of track and move it back and forth to work the lubricants into the gears.
6. Your truck should be free rolling and not jerk as you roll it. I usually try to get the trucks to roll down a piece of flex track raised only one inch at one end. This sometimes requires taking the trucks apart again and inspecting them closer, but you may not be as picky as I am.
7. Once you are satisfied with the free rolling ability of your truck, replace the side frames. For the most part there is no difference in either side frame, however, if you are working on one of Athearn’s new AC-4400′s there is a difference. For reference, the front right and rear left side frames are the same, and the front left and rear right side frames are the same. There is more information about this on the instruction sheet included with this kit.

Step 6: Reassembling the Locomotive

Once you have the truck reassembled, you can put it back on your frame. You should do this before removing your other truck so that you are sure they are back on in the right places. Putting them on backwards will cause your locomotive to run in reverse of any other locomotives you have.

1. Note where the frame rests on the truck (there will be a patch of bare metal here). Place a couple drops of the Conducta Lube & Cleaner here then place the truck under the under frame and set the entire assembly on your workbench.
2. Carefully pick up the worm gear and make sure no parts have fallen off. The spline that fits into the coupling is keyed and will only fit in one way. Align this part up first, then use the square washers to line the worm gear up with the worm gear housing.
3. Once you have the worm gear in place, but a small amount of “NG” Jel on the worm gear and replace the worm housing.
4. After fine tuning both trucks, replace the connector clip across the motor and assure that it makes contact with the trucks and the headlight assembly. For better electrical pickup, place a couple drops of the Conducta Lube & Cleaner on the top clip of the motor and where the connector clip touches the trucks.
5. Note: I strongly suggest hard wiring your locomotive even if you don’t plan to do any special lighting. I have provided instructions for hard wiring in a seminar entitled Hard Wiring Athearn Locomotives.
6. Place the shell back on by snapping the clips into their designated places. This is much easier then removing it as you already know how it comes off. I suggest doing this before testing it so that you will be able to hear the final result immediately.

Now that you have your locomotive reassembled, run it on your layout or test track. If your locomotive is as quite as you want it to be, then your done. If there is still some noise that you would prefer to get rid of, there are a few more steps you can take.

1. First, apply a couple drops of the Motor Bearing Lubricant at the ends of each of the splines and on any other moving part. I have found that it sometimes helps to put a drop where plastic meets metal on the flywheels.
2. You can also apply a couple drips of the Conducta Lube & Cleaner to the commutator of the engine. The commutator is located between the forward flywheel and the motor housing.
3. WARNING: Do not apply any lubricant or cleaner to the windings inside the motor housing. This can cause the wire to heat up and burn causing your motor to seize up. I learned this from experience, and would hate to find out others had the same problems.