Disassembly, Frame Work and Base Installation
CPR used FM H-16-44 on Vancouver Island and in the Kootenays on Kootenay and Slocan Lakes.
With Rapido uncertain about producing this model, I keep my eyes open for used ones online in CPR livery.
I bought this used model on EBay a couple of months ago (for a lot more than the original $26 sales receipt that was in the bottom of the box. Sigh) and accidentally shipped it to the farm. Now home at the farm for a week, so have started the conversion.
It’s going to get:
- A Decoder Buddy
- The biggest speaker I can fit
- A Soundtraxx TSU-21PNEM with Fairbanks Morse sounds
- New LED headlamps front and back.
- A rooftop beacon
- Ditchlights
It comes apart very easily by turning it upside down and removing two screws from the fuel tank, one coupler, and the four body screws in the bottom.
Turning the model over at this point the innards fall right out. Here is a picture of the inside with the 2 screws in the circuit board removed. I’ve circled the nubs for these screws in red and will grind them off with my Dremel so they’re not in the way.
Note the throw away lightboard! Harvest a PC Tie or two and some diodes perhaps, otherwise, just clutter.
The frame is reasonably hefty and held together by just three screws. The frame halves are insulated with black nylon bushings where the screws connect the halves and two white nylon insulators in the fuel tank. As well, the top of the trucks are accommodated in a recess in the frame and help keep the frame in alignment
I did some probing with an Ohmmeter before going further. Lots of potential decoder burnout pitfalls with this model. While the motor housing ends are plastic and isolate it from the frame (I note broken and missing pieces on my model - at $89 U.S., I paid about $40 too much for this specimen) brass wipers on both brush contacts make contact for electrical pickup from the track and will have to be removed. I’ve marked where I will nip them with a red line. This has to be done to both brush holders, although I’ve only shown one side. The objective is to have no electrical contact between the motor and anything else - it needs to be completely isolated and will get its power solely from the decoder via wire leads soldered to the brush holders.
Onto the trucks.
I’m not overly impressed with the brass wipers that make contact from the trucks to the frame. The part on the wheels is ok, but from there on too intermittent for my liking, so I will disassemble the trucks and solder fine wire onto the wipers and run those onto the Decoder Buddy. One could leave them in place I suppose, but then the frame is live and just asking for trouble given the tight quarters and as the contact did not seem that reliable in the first place versus straight to the wheel wipers I could not see the point.
Here I am using a small screwdriver to pry the side frame assembly and free the truck.
Here, I have soldered a small wire to the truck wiper. NOTE that I took the small screw out and did the soldering with the wiper in an alligator clip. This material is not pure brass (almost rings like spring steel?) and needs to get quite hot to take solder and I didn’t want to risk melting anything. It didn’t seem to lose any temper heating it enough to bond solder. Be careful with the trucks re gears falling out. This one has enough grease for a Kenworth so everything stayed put.
Here, an attached and a removed shot with the first wire soldered on before removing the frame wiper (confirming it would hold) and with red lines denoting where I will cut the frame wiper.
Here, rail nippers cutting off the frame wiper. Eye protection a must.
The fan housing on my model is an actual screen and I can easily see through it so I’ll mount the speaker forward under that.
Initial observation suggests that there may be enough clearance above the frame below the shell for the decoder and speaker but I will mill off some variability in the surface and some additional clearance for a proper isolation job. The circuit board in the roof (photo up above a few pics ago) was attached to incandescent bulbs and had diodes for directional control. This can be removed and discarded as I’ll be replacing the lamps with bright 2mm tower LEDs.
So back at this today, I took the bare frames out to the shop for some levelling and shaving. Probably about 30 thousandths as I didn’t want to completely shave the center screw hole. I already knew things fit so basically just making a bit of room for the double-sided tape.
I bought this mill brand new about 1984 and it is dead true in every possible direction. The power feed has a blown fuse or something I have to look into, but other than that it’s perfect and has done a lot of great work for me over the years. It has a battle scar under the vice where one of my daughters decided to use it to drill a hole through some wood and ran the drill bit right through and into the table. She said she didn't realize she was through and kept cranking. Thats the thing about the down feed on a mill - it is very strong! She got the "next time wait till Dad is home to ask and to guide" lecture and a hug. There was a cheap drill press right next to it with a hole for the drill bit. Lol. Kids 
The lathe I bought the same day was always weak in the top slide, and therefore useless for parting off. I also never really liked the thought of replacing a belt in the headstock if one were to break, so I sold it a few years ago and replaced it with a larger geared-head model that is a lot more robust (although it does suffer from a lack of a super slow speed). It's 12/16 " by 44" if I recall. I have a little wee variable speed mini-lathe as well, which is all I would ever need for anything up to G Scale. The lathe and mill are for my 3 1/2” scale live steam aspirations (have castings, but no time. I digress.)
Here’s the frame with some 6-32 alignment screws, vised up and ready to go. It doesn't look level, but it is - just camera distortion. I have it resting on a parallel under the fuel tank block, I actually checked it with a quill mounted dial indicator in a few places and it was within a couple of thousandths of level where it hits the body shell. In general, I find N and HO frames to be flimsy for milling, and they can’t be clamped tight without a lot of fuss and bother, so I just take really light cuts (< = 0.005”) and watch for any kind of movement.
The crew figures where there when I got it. I have no idea if they are factory delivered or installed by a previous owner.
This one squared up nice and the mill made short work of shaving 0.030” off.
Note the porosity in the frame casting. I would discover later that the frame is actually hollow. Glad I didn’t decide to chop it an eighth or more. Lol. I cleaned up the sharp edges with a file so as to not cut/wear any wires later, and went back to the train room workbench.
If a person doesn’t have access to a mill, there are a bunch of equally useful approaches:
- A suitable endmill can be bought for ~$5 and used in a drill press, with a decent vice and with or without an X-Y table (which I’ve seen at places like Busy Bee and KMS Tools fairly cheap, but only with very light cuts.
- A Dremel would work. Actually a Dremel drill press would allow for a nice finish and with a vice, a nice level finish. Just lower it 1/32” at a time and slide the frame under it on a flat surface on the drill press table.
- Another solution is a strong strip sander - they will rip metal off at an incredible pace. Much cheaper than a mill! If I didn't care about dead level, I would have just used this:
Next up, I round off the nubs for the old circuit board very gently and carefully with my Dremel. You can't see it well from here, but the fan shroud is a fine mesh screen and will let out plenty of sound.
I test fit everything after soldering wires onto the brush holders on the motor to see where to locate holes for the track pickup wires. I just realized that I never took a picture of the motor leads. Basically I just soldered a couple of inches of orange and gray wire to the top and bottom brush holders respectively, and heat-shrinked the end near the motor. There is room to run the bottom wire up beside the motor and they both fit nicely up between the frame halves.
I meant to heat shrink the truck leads as well, but forgot, but they don’t appear to need it from my attempts to create a short circuit.
I had to scrub and file this frame a lot as there was a lot of mold inside it. It came from the Deep South so perhaps it’s not uncommon to find this due to humidity and long-term storage away in boxes, etc.
Next, I drilled 4 holes for the truck leads with a 1/16” bit in a Dewalt 20 Volt power drill.
These battery tools are awesome, have bright LEDs to light up the work, and allow super slow speed control. I started the first hole from the top, and discovered while doing so that this frame is actually hollow. (Typical of this manufacturer, saving a few pennies and losing tractive effort while they’re at it). I finished it from the bottom, but on my second hole, I had already weakened the bit enough that it snapped off, so some caution is warranted drilling through both layers, or you’ll end up like me with a broken bit stuck in the frame! It's in there forever as there is nothing to grab onto to pull it - oh well, it adds weight and tractive effort!
Eventually, owing to the hollow center and the curve in the underside, I drilled the rest of the holes from the bottom towards the top on a square spot.
And here’s everything back together with all the wires carefully routed. To me, this is a lot nicer than trying to squeeze wires between the frame and the shell. They’re all safe and out of the way. I made sure to leave ample wire when I snipped them so the trucks could rotate freely.
Now, a wee bit of super sticky double sided tape … making a small channel for the motor leads ... which are through a mounting hole in the Decoder Buddy ONLY to hold the Buddy a camera pose!
And now the Buddy is all safe and secure …
And here is the progress so far with the Decoder aboard for a test. All systems go - everything installed so far checked out perfect. Love these Decoder Buddies - they make for quick and very tidy work, and the onboard resistors and removable light board are fabulous. I cut the rear track pickup wires really short and should have left a bit more length to aid in future truck removal. As it is now, I will have to unsolder them from the Buddy if I need to remove the truck. In that event, I'll install longer wires.
Since I didn't have my laptop in the train room, I was happy that I was able to do a fair bit of test programming (address, volume, prime mover select, etc.) directly via the Digitrax DT602D Throttle and new DCS240. I’ll do the harder stuff (flashing ditch lights, beacon and Function Key assignments, individual effect volumes, etc.) with Decoder Pro once I get all the LEDs installed, but glad that Digitrax got it right with the big command station versus the Zephyr I constantly fight with in Vancouver. It has proven useless in programming anything so I just don't bother. My dealer said to bring it in so they can try it out as they don't believe the challenges I have with it, so I may take them up on that in the event that it’s got a hardware issue.
Here's a quick video of conversion in action before moving on to tackle the lights.
That’s a Soundtraxx speaker and baffle, but smaller than the 28mm variety I normally try and use, which is too big for this model. I had this one in my parts bin and it sounds fine - I think it is the 20mm 3/4" job, but I didn't measure it. I have done a test fit and the shell goes back on just fine and sits level without hitting anything.
Sadly, as you can see in the video, typical of most of the Bachmann stuff I own, this model has some quirks. It runs very shaky at slow speed making one think the prime mover is missing all but one motor mounts. I think it is lash in the gear train on the front truck, but re-gearing articles so far seem to be hard to find. It smooths out at about 9% though, so will be fine pulling a train at speed. I had tested the motor earlier when I had it out of the frame and it ran super smooth on pure DC from my bench supply, so this why I think something is amiss in the worm gear/sprocket chain in the truck.
Digressing for a moment, a bit sad that this is Bachmann’s top end “Spectrum” level model. IMHO that just means it illustrates the full spectrum of their design and manufacturing processes at the time this model was made. Maybe they are better now, but I'm a skeptic based on a lot of experience. I am hopeful that Rapido will produce their planned version of this model as I need a fleet of these as I am contemplating an expansion of my Field to Golden layout to include the next leg to to Revelstoke and then south to the Kootenays in my grand plan.
Like many, I have a love/hate relationship with Bachmann. My first non-train-set locomotive was a
Bachmann 2-8-0 Consolidation, and I have several of their very nice On30 models - except for those crappy driveline parts of course, LOL. Ah well, I can fix just about anything. If anyone knows of a suitable gear train or truck replacement for this model, please do share the information here.
Next up, lights!
