the Doniphan Branch Railway

HO Scale Model
Notes on balancing the Athearn 2-8-2 "Mike"

Some people have had trouble keeping the front driver on the rails, presumably due to balance problems. Here is what Athearn had to say to Mr. Edward Oates, who emailed them about it:

It appears that in some locomotives the screw holding the main frame, boiler and weight (the screw that goes up through the bottom of the frame at the stack) is too tight, causing the frame to lift. They say that by backing the screw out a little, it should realign the frame and alleviate the problem. Additionally, however, we have found that the wiring harness that goes into the tender can cause problems IF it is not straightened out and flexed a little. We have been able to eliminate the problem with the harness in our testing here by straightening out the wires, then flexing it to get the wires inside the shrink tubing loosens up. Here is some more general information for you. The wiring harness of the Genesis Series USRA 2-8-2 Light contains nine (9) wires. They are used as shown below:

Gray - Motor negative
Orange - Motor positive
Red - Right rail pickup (engineer side)
Black - Left rail pickup (fireman side)
White - Forward light
Yellow - Reverse light
Blue - Light common
Green - Function 1
Violet - Function 2

Note that although the yellow, green and violet wires are included in the shrink wrapped harness, when used with DCC they would probably be separated from the wiring harness and kept in the tender.

John Engstrom
Athearn, Inc.
19010 Laurel Park Road
Compton, CA 90220

Subject: Fwd: Athearn Mike Fix
Date: Fri, 24 Nov 2000 09:40 +0000

Hey, Elvin,
Back some time ago, we corresponded 'bout increasin' the pull of the Athearn Mike. Well, I've been workin' at it. I made the followin' post, first. When folks got interested and wanted details, I made a big post that follows.

Hey, Y'all....'specially Earl & John.
I told y'all a couple days ago that I was workin' on addin' weight to the front of my Athearn Mike. Well, I did it and the locomotive pulls 26+ cars up that 1.5-2% grade with the curve at the top without slippin' a bit.

Now, I'll gladly share the technique with anyone who wants. If there's enough interest, I'll describe what I did right here on the list.

Wayne R. Long
Power to the Purple!

Hey, Y'all,

Seein' as how my report on increasin' the pull of my Athearn Mike interested some, I wrote the followin' description of what I did.

First off, the Atlantic Coast Line had no USRA Mikes. I bought mine at a good price from a fella who had bought several and was disappointed several times by their poor pullin'. I bought mine on the strength of the MR Trade Topics description of how smooth it runs and that it should pull 35 cars on straight, level track. I wanted that there smooth, powerful mechanism soz I could have me an ACL Mike by rebuildin' the boiler.

When I ran my new Athearn Mike it ran smooth, all right. Trouble was it wouldn't pull anywhere near 35 cars on straight, level track. Worse, it could pull only 'bout a dozen to 14 cars up a long grade that varies between 1.5% and 2% with a curve at the top. It would begin to slip goin' onto the curve.

My first step was to weigh the Mike. Weighed only 12 oz. That explained a bunch. Why, my USRA light Pacifics weigh 14 1/2 oz. and pull better!

My second step was to see how good the Mike was balanced. I removed the leadin' and trailin' trucks and put a length of 1/8" diameter brass tubin' on my desk and put the Mike on it soz the tubing was between the 2nd and 3rd driver sets. The 4th driver set set down on the desk. I pushed down on the stack soz the 1st driver set touched the desk. When I let go, the 4th driver set plopped back down. Now, I knew that besides bein' too light this here locomotive was "cab heavy".

Usin' directions Athearn mailed me I took off the plastic boiler. I found the weight was split down the center to carry both sides of the electrical power from the frame to the motor which was enclosed in the weight, at the back. Why, that weight didn't even fill the inside of the boiler. I took the weight/motor off the frame, clamped the front part in my vise, and hacksawed off the front one inch of the weight while I held onto the motor section soz it wouldn't hit the floor when I sawed through. Couldn't saw off more 'cause the Athearn weight is supported just back of where I sawed it.

My thinkin' was: lead is almost twice as heavy as steel for a certain size. So, if I replace part of the Athearn weight with lead I gain the difference. Well, Athearn didn't use steel for their weight. And, what ever they used seems not as heavy as steel.

Next, I made the replacement weight for the smokebox. I cast it out of plumbers lead soz it would fill the smokebox. Had to cut and scrape the inside of the smokebox smooth. I put a piece of tape over the front end of the Athearn weight to prevent a short when my lead weight gets pushed against it. I filed my cast weight so it would slide into the smokebox through the front with the plastic boiler in place. I filed a space all 'round the front of my weight to clear the tabs on the back of the Athearn smokebox front. If y'all want a workin' headlight file a groove front to back on the weight for the wires.

The part of the Athearn weight I sawed off weighs 'bout 1oz. My weight weighs nearly 4oz. So, I gained nearly 3oz. This extra weight just balances the Mike. Also, I packed some lead in the cylinders and on the top of the frame. My Mike now weighs a possum's hair less than 16oz.

When I re-installed the leadin' and trailin' trucks, I left off the springs. Them springs take weight off'n the drivers. I heard tell that one fella tried to "balance" his Mike by increasin' the spring tension on the trailin' truck. 8)

One more thing 'bout this Mike. It's boiler's not wide enough. Athearn made it the size of the USRA light Pacific, I believe. These 2 USRA locomotives used different boilers. If the boiler was bigger, jus' think of the extra weight we all could add.

Now, if any of y'all are interested in how I cast that there smokebox lead weight let me know an' I'll get to writin' about it directly.

Wayne R. Long
Modellin' the ACL in 1950
Let me know if any of this helps.
Have a real good Thanksgiving.
Wayne R. Long
Power to the Purple!

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