I still see posts asking for help to repair this otherwise fine engine. Those thin motor wires are the culprit which is an easy fix but that boiler removal--hoo boy. So here is a reprint I posted from a few years back on a newsgroup. I incorporated several other good instructions from other posters into it, including Athearn's. BTW when I found out about the cracked gear in this loco, almost ten years after I bought it, I emailed Athearn and they sent me a brand new gear axle with drivers attached, free of charge. They are great people! Anyway here's the boiler removal instructions from rec.models.railroad, 2002:
Repairing and weighting Athearn Mikado--Update
For the past three years a number of us have experienced problems with the original issue Athearn Genesis Mikado: poor traction, the stiff umbilical, and engines suddenly gone dead. I finally got up the guts to take mine apart and solved all three issues. My thanks to all those before me who have posted their knowledge and know-how dissecting the Mike. I'm an electrician so I'm adding all electrical knowledge of this adventure that I've learned.
I recommend a mandatory repair for every Athearn Mike owner to re-do the two wires attached to the weight halves. Many of these connections, if they don't break off entirely, are hanging by a strand or just making a pressure connection. The resistance buildup would affect engine performance for the life of the motor.
I thought I could get away with weighting the loco externally, because the instructions I had so far read about disassembly sounded formidable. After manipulating the wires between cab and tender one day I ended up with a dead loco. I decided a round trip to Korea and back for the patient would take too long, so I printed up Athearn's disassembly instructions (and several others from rmr posters) and jumped in. I ended up taking my Mike apart three times and it turned out to be a piece of cake once past the fear stage--like so many other things in life.
Here are Athearn's instructions with my comments (*) interspersed--because Athearn left out some critical details.
1. Take off the cab . . .
*Remove the two cab handrails first.
a. lift the rear of the cab to release the two rear tabs (small screwdriver carefully inserted at bottom rear of cab will help)
*Take your time--first removal is tight. Alternate from one side to the other with the screwdriver or exacto blade.
b. insert screwdriver at front side of cab between bottom of cab and walkway and carefully spread side of cab away from boiler to release small tabs at front bottom of cab (much easier to do than to describe).
c. lift cab straight up and off of boiler.
2. Remove smokebox front and unplug two wires (use sharp tweezers to pull plugs straight down).
*Take note of the polarity for later--white goes to white.
3. Remove the boiler to pilot deck supports (we'll get the correct term for future use)
*These are the black diagonal rails between boiler front and pilot.
4. Remove screw from bottom of frame that goes up into stack
*Remove the black gizmo just forward of the walkway on the engineer's side where the silver section starts. Pull it straight out with a needlenose. It goes back the same way.
5. Insert screwdriver at rear of boiler above walkway and carefully pry boiler rear upward. Do this on both sides to release the tabs that hook the boiler to the walkway.
* With a small implement push those black tabs in alternately to help release the boiler.
6. THIS IS THE TRICKY PART . . . after rear of boiler is released, lift rear of boiler to clear the weight, then CAREFULLY slide the complete boiler forward. May need to wiggle it as you slide it forward. Boiler comes off, and you have the innards exposed.
* The boiler will not break, even though it feels like it will. Tip the rear end as hard as you like until it just clears, then slide the boiler SLOWLY forward with a side to side wiggle. At the same time gently squeeze the front of both walkways inward to release the tabs gripping the inside edges of the boiler front.
7. To take out motor and boiler weight, there are four screws to remove. Two screws are at rear, with red and black wires attached. Two are on each side near front of weight, above walkway, just behind centerline of axle of first driver. Take out these four screws and motor/weight assembly comes out.
*First the wiring fix. (I recommend) cut off the black tubing completely. It's too stiff and derails the tender. The green, yellow, and violet wires are not connected to anything and are for optional DCC functions. Pull them back over the DCC plug and secure with electrical tape. Tightly tape the remaining wires with a short piece of black vinyl electrical tape. I was able to flatten the bundle to reduce the profile.
* (Do not re-use the factory connectors!) This is a finely crafted loco but the wire connections to the weight halves are extremely delicate and unreliable. The solder connections on mine were both broken. When it comes time to reassemble, clip the wire ends clean and strip enough insulation (3/16") from each one to wrap under the screws directly, now using the connector as a washer between screw head and wire. Twist the strands tight and pre-form the stripped wire into a tight circle. Position the loop over the screw hole. Insert the screw and tighten. Point the connector shanks straight down. The red wire goes to the engineer's side, black wire to fireman's. This may need the patience of a watchmaker, but take the time to make a good solid connection or it's disassembly time again. This is your main connection between the drivers and motor--it's important.
*DO NOT CUT THE UMBILICAL OFF because the red and black wires go through the DCC plug and come back as orange and gray for the motor. Even if you spliced these, you still need the DCC plug for the headlight directional diode built into it.
*Remember--the black weights are electrically live so depending on where you insert lead to add weight, it will short out the loco in any region bordering the two halves. Either tape the weights appropriately or wrap the lead with tape.
*THE LEADING TRUCK USES A FIBRE INSULATING WASHER BETWEEN FRAME AND SPRING. IF YOU REMOVE AND THEN REPLACE THE SPRING, DON'T MISTAKE THE FIBRE WASHER FOR THE METAL WASHER OR YOU WILL CREATE A SHORT!
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
*That ends Athearn's info. Here is how I weighted my Mike, which I guess applies to the Pacific too. I used the experience of those before me and a little of my own added. Note: although lead is ideal, for health reasons I used copper stock which is almost as dense.
Fill the sand and steam domes with lead shot or lead pieces or fishing sinkers. Seal the lead in with ductape. Make sure the lead doesn't protrude too far out of the recesses or the boiler won't fit on.
I didn't feed lead shot into the cylinders out of fear of the rods jamming. Do this at your own risk. Obviously don't fill beyond the level of the rods, but if the shot balls pile up at one end you risk a toasted motor.
Seal the bottom of the steam chest (where the screw came through) with ductape, enough to also drape up the sides, covering the cylinder access holes. Fill this with lead shot and seal the top off with more tape maintaining a clear curve for the boiler to rest on later. OR, skip the ductape and shove lead sheeting diagonally into the cylinders above the rods, then pile up little square pieces or sinkers to fill the chest. You don't need to replace the long screw. The tiny screws at the bottom of the chest need to be insulated--they are common to the frame.
Cut lead sheeting or sinkers to fit between the leaf springs above the drivers. Don't go too thick or the boiler won't sit right. Paint the lead black. This arrangement is not prototypical but it's hard to notice. You can pile a good ounce into this area.
Likewise under the driver assembly. Flip it over. Thin lead sheeting can slip under the brake mechanism truss rods, between the first drivers, and between the cylinders. They need to be glued. To remove the brakes pop them out of their pegs near the drivers. The little truss rods are fragile and will snap if bent too far. Paint the lead black. The two tiny screws in the middle by the manufacturer's info plate need to be insulated.
More thin lead sheeting can be curved and slipped under the boiler weights after this section is mounted to the drivers. Tape the lead up with electrical tape to prevent a short. The pieces cannot extend above the level of the walkways or the boiler won't fit right.
After the boiler is reassembled, lead sheeting can be curved and shoved between the boiler walls and the weights, and around the front of the boiler. They need to be insulated with tape first. Make sure it's a loose fit and accessible to pull out or the boiler will never come off again. Leave room to re-connect the headlight and for the smokebox front.
Before mounting the cab, glue or tape more curved lead under the cab roof. Not too thick or the cab won't fit right. Paint it black.
A feedwater heater can be made from lead and glued forward of the stack. An air tank can be placed at the rear of the pilot between the ladders. (credit goes to Hazen for these two) Or one could fashion plastic cylinders and fill them with lead. That can add a good amount of weight.
The Athearn Mike weighed in at just above twelve ounces out of the box. After I was done adding just copper, I increased this to nearly fourteen ounces. Using lead will probably give you fifteen. 2-3 ounces added is ideal. (according to Hazen) The loco no longer slips going up even a 10% test grade.
Good luck to all.
Very nice as I am looking to get a Genesis 4-6-2 and might have to do the same. Dave at NWSL has told me he has the gears also. I have used NWSL gears and I like them.
By the way, pictures would be nice also as a picture is worth a thousand words.
I have copied and put the instructions in a document for future reference.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
I got my four Athearn Mikes up to 16.75oz (loco only) and managed to keep it balanced, too, which is equally important as the added weight. I also removed the pigtails completely, as I run DC. I added tender pick-up, too, using Bachmann trucks. So far, no issues with the gears, and these locos are used on heavy trains.
There's a full how-to, with lots of photos, here:
bigbluetrains.com
Wayne
Hi doctrowayne
Thanks. I just joined.
If I have to add any weight to the 4-6-2, I will use lead bird shot. It fits in real well. I have a digital scale for weighing this stuff.
Hope you find some useful stuff there, Rich.
sorry to necropost , but this is soo useful it should be a sticky , i unpacked my 2-8-2 & the cords are broken & she broke i thought i was the only one that had a hard time getting the boiler off , thank god im not :)
Actually, for Step 5, simply squeeze the boiler immediately above the back end of the running boards, and as close to them as possible, to release the tabs in the firebox. This way, there's less chance of breaking the tabs than by prying.
Would anybody care to give a step by step on how to replace a gear on the 4-6-2? I am about to get the NWSL gear and need to replace it. Thanks so much!
The gear replacement itself is quite simple, but you'll have to go through the disassembly procedure to get at it.
If you go to the link which I posted above, the gearbox is shown in the second photo sticking out the bottom of the boiler weight, and in the third photo, laying beside the motor. Simply separate the two halves of the gearbox, and replace the gear.
Awesome instructions im in the middle of doing this repair finally, need this to be a sticky
The timing of this posting is perfect for me.
Yesterday I was cleaning out a part of the garage that I used as a workbench area for my model railroad layout before I had a small workshop built.
I had quite a collection of small boxes, mostly clearly labeled that I have been going through and sorting. One of the smaller boxes that had fallen on the floor and was more or less caught between an extension cord and one of the bench legs had not even been opened.
I opened the box and found one of the replacment gears with drivers that Athearn had sent to me years ago shortly after the release of the troubled Mikes.
So I tracked down the Athearn Mike and put the replacment driver in the box with the engine. I had forgotten about that engine and had shelved it untill I could get a replacment gear from Athearn.
Unfortunately I doubt I will ever repair that engine now. I no longer have any use for it as I have since downsized my layout and I only model the CNR, CPR and GN roads now and have no use for an USRA Mike.
I put a note with the part and copied onto a CD most of the information given on this posting as to repairing the engine. So at least one day someone hopefully will update the engine and it will be on someone elses layout.
don7...Unfortunately I doubt I will ever repair that engine now. I no longer have any use for it as I have since downsized my layout and I only model the CNR, CPR and GN roads now and have no use for an USRA Mike.....
The CNR owned 40 USRA Mikes, originally built for the Grand Trunk. They also owned a bunch of USRA copies.Here's an Athearn Mikado which I modified for a friend:
I hadn't known when I did the work that the 3736 was never equipped with an Elesco fwh, but he requested it. I'll be doing another one for myself when time becomes available.
doctorwayne don7 ...Unfortunately I doubt I will ever repair that engine now. I no longer have any use for it as I have since downsized my layout and I only model the CNR, CPR and GN roads now and have no use for an USRA Mike..... The CNR owned 40 USRA Mikes, originally built for the Grand Trunk. They also owned a bunch of USRA copies.Here's an Athearn Mikado which I modified for a friend: I hadn't known when I did the work that the 3736 was never equipped with an Elesco fwh, but he requested it. I'll be doing another one for myself when time becomes available. Wayne As always, your work on modifying the Athearn is stunning, to say the least. Yes, I keep forgetting the Grand Trunk. thanks for posting the picture. As i said i have downsized and have way more engines and rolling stock than I will ever need or use. I much prefer to model the smaller branchlines with the smaller steam, just lover the 4-6-0 engines used by both CN and CP plus a few 0-6-0 switch engines and that would do me fine.
don7 ...Unfortunately I doubt I will ever repair that engine now. I no longer have any use for it as I have since downsized my layout and I only model the CNR, CPR and GN roads now and have no use for an USRA Mike.....
As always, your work on modifying the Athearn is stunning, to say the least.
Yes, I keep forgetting the Grand Trunk. thanks for posting the picture. As i said i have downsized and have way more engines and rolling stock than I will ever need or use.
I much prefer to model the smaller branchlines with the smaller steam, just lover the 4-6-0 engines used by both CN and CP plus a few 0-6-0 switch engines and that would do me fine.
Thanks for your kind words, Don.
I'm running a couple of freelanced 10 Wheelers and a couple of freelanced Moguls, too, but also have a CNR 0-6-0 and a 10 Wheeler.
The 0-6-0 is a cast-off from a friend:
...while the 10 Wheeler was a bargain because it lacked its original box - not a concern, as I've modified both locos, destroying their collector value
If you're thinking of selling that Athearn Mike, send me a PM.