Good evening TrainBoard, I just accomplished the complete disassembly and reassembly of the InterMountain AC-12 Cab Forward in less than 45 minutes! Edit:*er, well, of the shell, not mech.* This was my very first attempt and I even snapped photos! Before I began, I was scared to death about this procedure as the AC-12 is the most beautifully detailed N Scale product I've ever known. But during the process I found that many of the detail parts are very flexible and forgiving! I rate this procedure no more difficult than any other N Scale steamer out there! Well, lets dive right in, shall we? Step 1: Carefully pry off the Steam Turret and Feed Water Heater to reveal screws underneath. Two pipes will likely come off with the Feed Water Heater, and a third will need to be lifted and moved aside. Step 2: In order to lift the boiler shell, the hand rails and piping must first be slid out from holes in the rear of the cab. The hand rail and similarly sized piping will slide straight out, however on the engineers side is a larger plastic tube which must be kinked away from the boiler in order to slide out. Don't worry, as I said before, this part is quite flexible and forgiving. To lift the front of the boiler, some detail parts will need to be moved out and around others. Again, these parts are quite forgiving. Step 3: To remove the PC board, first remove the screw below the wires. The thin wires are for the forward lights and are extremely delicate, more delicate than any of the detail parts. (And yes, that is RUST on the motor case! ) ...continued.
Step 4: In order to gain more slack to remove the locomotive PC Board, unplugging the wires from the tender may be necessary. To remove the tender shell, simply pry the shell along the bottom and lift up. Be extremely careful as more of the delicate wires connect the tender light to the tender PC Board. Remove the screw to the rear of the tender PC board to gain better access to the plug on the underside. Unplug the plug. (By the way, I noticed the spacer between the PC board and tender floor was an HO sized bearing block! Nifty innovation of part use InterMountain!) With more slack on the Locomotive PC Board, you can move it out of the way enough to pry the rear of the motor upwards. When the motor is lifted enough, the connecting shaft to the rear drive train will pull out from the flywheel. You can then rotate the motor to position the forward drive set to the desired offset. Step 5: With the offset in the position as desired, press the motor back into its clip. Mine made quite a snap that worried me at first, but after inspection, it appears that is just the sound it makes. Next simply re-assemble the locomotive following the reverse of these steps. The only step that was difficult on the reassembly was replacing the details that were removed with the Feed Water Heater, but it was only difficult in getting the parts into their proper place. With patients, I had them set in no time. Here is a shot of my reassembled AC-12 and it's newly offset drive sets. I hope this helps anyone with the desire to offset their own drive sets!
Great post and good pic,s i just got one for my birthday. Boy this is a real sweet loco and a good puller. Do you remeber what the leds look like? thank,s Don
Hi Don, Unfortunately, no I did not get a look at the LEDs. You can remove the cab roof by simply prying it up (its press fit). Inside I saw no LEDs visible, but there is concealed clear plastic which channels light to the Trainboards. I expect the LEDs are further concealed somehow so they do not bleed into the cabs wonderfully modeled interior.
Alternative Disassembly! As with many jobs in this hobby, there is more than one way to gain access to the internal parts required for gear lubrication or driver re-position. This one is WAY more simple than the previous and can be done in as little as 5 minutes. Simply invert your locomotive. I tilt the tender to the side which helps stabilize the locomotive. You can also use a cradle. With a jewelers flat-head, pry the plastic break shoe part upwards. Then with a Phillips, remove the two screws shown. Remove the bottom plate, and you're in. Simply lift the geared axle slightly and rotate to the desired position. When replacing an axle, be very careful not to inadvertently bend a power contact. There is a tab for each wheel, and must be positioned between the two wheels of each driver. If you simply force the axle down, you will ruin the integrity of the contact and lose it's position and springiness (yes, that is a word). Then, replace the base plate, screws and plastic part and the job is complete!
While you have the baseplate off, it's an easy job to swap the traction-tired drivers over on the REAR set, so the TTs are on the rear drivers, not the front. Simply pull out the crankpins and they can be changed. You can't do this on the front set as the TTs are on the geared ones.Makes a great difference to pulling power.
As long as you are careful not to torque the wheels on an axle, the quartering should stay set. I assume there's a little bit of tolerance as result of only one axle being geared and the rest being driven by the rods but in any case, just avoid twisting any wheel.
I refrained from doing this just yet as I was uncertain about how to remove the crankpins. Are they screwed into the wheels or simply press-fit? I noticed all the pins have a hex-head instead of the usual round head which leads me to wonder if they are tiny screws at the tip.
Hi Mark. no they are just press fit. I placed a stanley blade behind the rod and rocked it and the pins came loose. Small pliers or tweezers can then pull them out.
Mark, or anyone, do you know how the tender trucks are removed, the insulator of the wire is stripped for some reason and I am trying to solder a new set of lead to the truck's power pick up, thanks.
Are you guys kidding me!!!!! I don't see one shaking nervous hand in any of the photos. I not only love that new AC-12 by IM, but highly respect it, and honestly, would never have the "stuff" to even think about disassembly or reassembly. Right to the factory and write the check. This comes from a guy who has a complete dedicated model/hobby workshop with just about every magnifier, lighting, tool and supply I can think of, and I have performed lots of repairs, upgrades, modifications, kit builds, bashes, scratches, and even taken apart a lot of locomotives. But I get the incredible "NERVOUS NELLIES" when trying to take apart some of the new steamers. I stopped my curious disassembly when I got my first Kato Mike. I have no qualms about older Rivarossi's, Trix's, Atlas's, Bachmann's and ConCor w/ or w/o Kato's, but I just hope the respective factories have warranty/repair facilities for anything issued after 2000. I just don't have anything but the highest respect for you guys taking apart a $300 loco. wowser. Just my $.02 to give you guys the props. Ken "FloridaBoy" Willaman
Oh, Mark! Hasn't anyone told you, "You don't fix it if it ain't broken". Gosh you trying to scare the poogiebies out of me. Leave that darn thing alone. Unless you want to brag you took it apart and put it back together in 45 minutes but you decided it would be better for all of us if we didn't learn...that it doesn't work anymore. LOL Dang Mark, my heart stopped, it took two quick cardiac thumps on my chest to get it started again and the Nitro...the nitro... I had to take, never mind the head ache that followed. Quit That!
The tangerine colored LED needs to go both head and tail lights are glowing unnaturally, I have to thank Mark for disammble the whole thing otherwise I would be yanking the boiler alone with screws attached. Can anyone shed some lights on how to take the damn tender drucks out?
Ok, Mark, you already have earned some very serious bragging rights for other achievements. When I saw the title I cringed - even though I'll never own one. Then I started reading. What is really cool is you come across so modest. Take a bow, well, at least one that fits who you are, take a bow. Addendum: I posted this at the end of page one never having seen Rick's response.
Well my pair work much better since I swapped the drivers over, so the traction tired ones are at the back, and I removed the springs under the trucks. They were way to stiff, causing the drivers to lift.
Hi Bob, How did you actually remove the pins from the frame, are the pins pressfit or screwed in, thanks.
I assume you mean the pin holding the rear truck. I couldn't shift it, so I just grabbed hold of the spring with some fine pliers and pulled it out. If you mean the siderod pins, they just pull out of the wheels. I used a blade under the siderod to lever the pin out.
