I just got an Intermountain Cab Forward and I gotta Say I am a little underwhelmed with the performance of it. First off I am running a temporary setup while i am building my new layout using Kato double track with the superelivated curves (16" outer 15" inner). The loco keeps losing power on the corners. And when it doesn't cut out in the curves it completely looses traction. I only have it pulling 20 cars and the setup is completely level. Anyone have any advice? I love this loco and I don't want to have to keep it in the engine house. :tb-sad:
How often do you have feeders dropped? The loco picks up power from the drivers, and also one rail per tender truck, so its gotta be quite difficult to loose power via pickup. I assume you've ran other locos through the area. Have you noticed any hiccups or slow downs with them? Losing traction is also tricky one. The traction tires are installed right? (Just touching the basics). One other thing you might check is the plow. It hangs down super low and might be catching uneven rail head, or even stalling on dips or humps. (Again, I know you said the layout is level, but just touching the basics) Is possible the super elevated curves could affect this as well. The only other thing I can think at the moment is to ensure the engine trucks are able to move freely up and down. If they cant, then they're not properly following the profile of the super elevated curves which could affect both traction and pick up.
I don't know if this applies to your situation or not but, I have discovered with mine that in a right hand curve of less than 14" radius, the lead truck "slides" under the pipes under the cab and literally lifts the left side drivers off the track thereby decreasing some of the traction. I haven't had the heart to do any cutting on this expensive machine but, I will eventually remove the bottom pipe to give the truck more clearance. This may be the reason why IM recommends the minimum radius that they do.
So far all of my other locos work just fine, its looks like its losing contact. As far as the track goes I have checked it and it looks fine(its kato unitrack after all). I am thinking it could be the pivots for the driving wheels. How would I adjust those?
On mine, each driver set has about 15-20 degrees of rotation up and down. That is more than plenty for accommodating 15" super elevated curves. Before adjusting anything, just lift the nose with one hand and wiggle the trucks with the other (grab by the piston cylinders, not the rods!). The amount of movement should be intuitive to whether or not it's restricted in some way. If its unrestricted, it will be clearly so, but if it is restricted, you might ask your self if it's supposed to move more (in which case it probably is). absnut also makes a great point about the details getting caught. Run it very slow and carefully watch each side of each truck to make sure no boiler details are catching on any of the side rods. Check straights and curves and watch each wheel for several rotations. One other thing to inspect is the tender trucks. Since each truck only picks up one rail, perhaps the tilt of the super elevation is causing a break in the pickup at the tender truck. Sometimes when I experience a stall, I apply very light pressure to a specific part of the pickups (reach in with a toothpick or something). If slight pressure at one contact causes the loco to go, that's often the sources of the bigger issue. It's a lot to watch for, but once you figure it out and pinpoint the problem (and then correct it), it will all be worth the effort, and you'll soon want 2 more AC-12s!!
Dont forget....if you cant figure it out, return it to Intermountain. They have excellent customer service and will fix or send you a brand new one.
Sorry if abit o/t,but has anyone had any luck with IM spare parts? Im still chacing 2 x cab forward cabs, cab/boiler..........
Run your fingernail over the rails, in both directions, and see if you are feeling any "bumps" at the unijoiners. Mark's comments about the pilot plow (cow catcher) -- it is so low, it can catch on the smallest edge. Also, check the coupler pin, that it isn't hitting a rail or even a molded in tie! Remember, the pin should clear the rails. These AC12s are the best units for ensuring your track is assembled perfectly, but once done, they are a joy to run and watch!
Well, I have 2 Intermountain ACs and like them both although I have had some of the same troubles as others. AC # 1 tended to stall out in the curves while pulling 20 or so cars around level track (I'm not sure what the radius is, but its the "Salt Lake Route" plan from MR and is a pretty generous radius). Anyway, I cleaned the rails many times with minimal results. Last night I was running the AC with about 17 cars and noticed that #1 was running very smoothly with no stalling for quite some time now - it must be broken in now as it runs very well with no stalls. I had to sand down tiny mismatchs in the tracks that the front of the locomotive tended to catch on as well as bend the coupler hose out of the way. Its a great runner now although I suspect it will never pull like my Challenger. Next step is to install the Tsunami cab forward DCC/sound unit. AC #2 was the first to get the Tsunami and Wow!, the sound really brought memories. I'm old enough to remember the cab forwards and I used to go to sleep at night listening to them sitting in the Gerber, CA yard (stay over at my cousin's house). The Tsunami units sound just right to me. Unfortunately, I wasn't happy with the way #2 ran. It had a "lope" to it that would't smooth out. I turned it over and looked at the mechanism with a magnifying glass. One driver seemed to be bent and I could not straighten it. I removed the Tsunami and sent AC #2 back to Intermountain. I received a package from Intermountain in a few weeks that said they had given me a new locomotive. I still need to install the Tsunami and test it, but it looks good and I am looking forward to double-heading the 2 with Tsunamis in both of them. Gerry
I looked really close at it in the middle of a curve and noticed the front set of drivers on the higher side of the superelevation seems to be lifting. I checked the travel of the drive bogies, they don't seem to have that 15/20 deg of play that you were talking about. I checked the details in close proximity of the drivers, I don't see anything hitting. I also checked the tender trucks and all six axles are planted. I have looked very closely at the front of the loco. nothing is catching. :tb-sad: I may have to do that if I cant get this thing running right.
I have this exact same issue with my second one in the very same situation and I can not figure it out so it has become an expensive mantle piece. Mike
Yup all points lubed. I was hoping you would chime in on this since you are running the same type of track. So, you have one that works fine and one that is doing what mine is doing, correct?
No , I had one that ran perfect for about 60 hrs then it threw 2 side rods. I sent it in for repair and got this one back and now it does as your does. Thanks , Mike
You may find the drivers are lifting because the springs under the front & rear trucks are too strong. I removed them on my ones and it made a great deal of difference.
AH HA! I have solved 2 of my three problems. I did the spring elimination on the front truck, that fixed it riding up over the rail on curves. It didn't fix the problem of it acting like it was on greased rails in a curve. I continued to look for the problem and i noticed if I put pressure on the side that leaned inward it found traction and kept going, I looked back and forth on both sides looking for somthing that was rubbing. I finally spotted the problem where the boiler overhangs the platform there was a bit of detail that was too close to the platform and was causing it to lift the whole boiler when in a curve (see photos). A little filing later and it is pulling 42 cars around the curves with almost no slipping. I think I have isolated the problem with the loco losing power on the curves and it seems the tender wasn't as "planted" as I first thought. If I add weight to the right side it keeps going. How can I fix this without having to take apart the tender and add weight?
Glad you are on to a couple things , that will give me a place to look. Good luck with the tender. Mike :thumbs_up:
The tender opens up very easily, to access the NMRA plug, so you should be able to add weight internally. If you want to add externally, you might want to get some golfers lead tape, and apply to the bottom of the tender. This is the weighted tape golfers use to add weight to their club heads. Available, cheaply, at most sporting supply stores.
