I received one of my “new” acquisitions in the mail today: A brass Alco Models FM H20-44 switcher. I removed the shell and used my $20 Sears multimeter to check the motor brushes and points on the frame for continuity. Below is a picture of one half of the chassis:
I get continuity between the screw (that the red motor wire is attached to) and only the areas in the red circles. The opposite end of the chassis is a mirror image of this one and I get identical readings from the same contact points; the one exception being the wipers on the opposite corner truck. All other points from either screw show an open circuit.
Is it logical to say that the brushes are sufficiently isolated from the frame?
I would agree with you that the motor brushes themselves are isolated from the frame and that method you show is pretty common among brass manufacturers for collecting current from each rail, thus each truck is “hot” to the corresponding rail and only a pair of wheels on each truck are insulated at the axles. There may be fiber “thrust” washers at the end of the axle at the insulated side as well to prevent the insulated wheel from touching the side frame.
In its simplest form you could place the black and red wires to each bolster screw and the orange and gray wires to each motor lead and you’re done.
To be sure, remove the wires at the bolster screws, power the motor with a 6-to-9 volt DC source, a battery works fine, then check for voltage between each motor terminal and any metal on the frame/trucks.
This engine is a good candidate for a keep-alive capacitor, too, since you only have a total of four wheels collecting current.
I might suggest placing strips of Kapton tape on the bottom-side of the frame, above the truck side frames, to help prevent any short-circuits in the event of a derailment.
You should be good to go. I’m not sure what motors they used, but that one must be a newer model, looking at older issues of MR when Alco Models was still in business, they often had the typical open frame motors which typically are the type to ground one brush wire to the motor frame and generally only have 1 pickup wire (the frame of the motor and loco chassis is the other side).
As it happens, my one and only brass model is an Alco Models product as well - but a namesake Alco RS3 (you know I love RS3s, right?). Someone actually had already replaced the stock motor with a Sagami can motor AND it had a DCC decoder in it (really ancient Digitrax one - installed exactly how you SHOULDN’T install a decoder - a ton of sticky-tack holding it to the shell). The entire drive train was reworked with what looks like a scrapyard special - whatever parts were on hand, some Athearn universals, some other brand of dogbon on the other end in an effort to give some lateral movement, etc. The short hood end was just unworkable, there was no lateral play at all so if the truck tipped up or down at ALL (I had no grades on my layout) it would bind. My temp fix for that was going back to the old RC fuel line method of making a drive shaft, so it runs now but still needs cleaning up. Plus taking it apart dinged the paint so I need to either touch it up or just do a full repaint. Someone did go to the effort of adding the steam loco type markers on the corners which is a proper detail for Reading. I would just do a paint touchup except the decals also have some issues with lots of air bubbles under them, so it may be better to just strip it completely and repaint.
Good suggestion, Ed. I had originally planned on bringing one of my MRC Railpower power packs with me to PA to test-run the H20-44 on DC when it arrived in the mail but I forgot to pack it. [:(] For a quick 'n dirty I guess I could try powering it with a 9V battery?
I am contemplating a keep-alive module, as well as whether I want to go sound or non-sound DCC. While there seems to be room inside the shell - especially under the driveshaft areas - the motor wires (on the base floor) and cle
The motor that came with the H20-44 is a 12V Taneda can motor and it does look newer, Randy. I’ll be curious to find out how quiet it is. I’m going to guess that the drivetrain is going to be the noisier of the two.
Another forum member, Tom (ACY), said that the gears on these units were prone to cracking. As a backup plan I think I’ll look at what NWSL has to offer on replacement gears.
That may be your deciding factor on weather to install sound or not [:^)]
I have a 1961 vintage LMB NYC H10 I’m presently working on and the drive-train is mostly open gearing. In order to quiet the gears down I have to find just the right viscosity of thick oil or grease that will do the job but not get slung all over the inside of the engine.
In your case the motor shaft itself has an open gear and that little gear is going to turn at motor speed. That may prove a challenge. You might want to provide a fabricated styrene “housing” around those gears, even as a shield of sorts, to help keep those fine decoder wires from getting chewed up.
Correct on the Kapton tape, just to add a little insurance. With the motor truly isolated you won’t risk toasting the decoder but I find some brass engines “fussy” when it comes to preventing shorts and any path you can easily eliminate should be considered.
I’m not so sure the noise is generated just because the gear is exposed, but rather it is only supported at one end in the tower, the other end, since it connects to the universal jointed shaft, pretty much is free to flap in the breeze, which is surely will because NO ONE ever took the time to perfectly balance the shafts or the cups (if it’s even possible). What you get is vibration with constantly is varying the mesh of that small gear and I suspect over time ovals out the whole in the tower that mounts the other end of the gear’s shaft, which just makes it worse - and keep getting worse. I’m thinking the whole thing could be dramatically improved by bending a piece of brass 90 degrees and drilling a hole through it and adding a bushing for the motor side of that little gear’s shaft, with the other end screwed to the top of the tower. I may try something like this on mine when I fix the drive, it’s something I can do with the tools I have.
My only point is that it is difficult to keep lubricant on an exposed gear, especially one that rotates at motor-shaft speed, and not being able to keep a “supply” of grease on the gear, as you can in an encased gear housing, eventually the lube will be slung off and more noise generated.
Admittedly, even some enclosed gearboxes are noisy. I actually like the way the old Life-Like E units sounded. They were heavy and the gearing actually made them sound—*almost—*like an EMD!
Okay, Ed & Randy…I’m just double-checking this because I’ve never hardwired a decoder into a locomotive that didn’t have separate wires for conveniently hooking the track power and motor wires to the decoder.
At present there are only two motor wires: One is attached to the bolster screw/track pickup at one end and the other wire is attached to the bolster screw/track pickup at the other end. In order to hardwire this to a decoder I need to:
Split the motor wires in the middle
Red pickup wire goes to Pin 8
Black pickup wire goes to Pin 4
Motor wire (connected to red pickup) goes to Pin 1 (orange or +)
Motor wire (connected to black pickup) goes to Pin 5 (gray or -)
Yup. This loco just has a wire going straight from the pickup to the motor instead of a wire from the pickup to a board, and another wire from the board to the motor. Electrically it’s the same, so just splice into the wires, or you can desolder the wires from the screws and solder the red and black decoder wires in their place and connect the orange and grey to the existing wires. Or maybe just go all in - unsolder the existing wires from both ends (should be soldered to the motor tabs - if not, ignore the rest of this) and solder the red and black decoder wires to the pickup screws, and solder the orange and grey right to the motor. No extra wires or splices to worry about.
Thanks for confirming that, Randy. I just wanted to make sure I didn’t miss anything. [:D] I’ll be sure to post some pics when I finally convert it to DCC.
The picture shows a gear tower very similar to the Hobbytown tower. Hobbytowns aren’t exactly quiet, but they’re not incredibly noisy, either. To me, anyway.
I’m working on a couple of Hobbytown powered switchers. I intend to add sound partly to minimize any gear noise. And I will definitely be using “keep-alive”, as it’s only 4 wheel pickup. Which is what I think the subject model is.
One of the shells is cast metal (Varney). The other is plastic (P2K). I do wonder if the plastic will be noisier. It probably doesn’t matter, because the way I’m setting it up, the inside walls of both shells will be lined with about 1/16" thick lead sheet. Which will likely damp a lot of noise, anyway. I suppose one could do the same thing for a brass shell.
I temporarily installed a spare TCS M1P decoder that I had laying around in my H20-44 and got it running. No smoke so it looks like everything is isolated properly.
Not surprising there was occasional hesitation at speed step 005 and < that required a push or two to get it moving again. I decided to break-in the H20-44 on my 27" long programming as I watched Star Wars: The Force Awakens. Needless to say there was a lot of back and forth.
The good news is that, after about 45 minutes of break-in, the H20-44 will now run consistently - without any hesitation - on speed step 001 at ~0.25sMPH. There is some gear noise at higher speeds. Perhaps this will subside some once the gears and grease wear in a bit more. I don’t expect it to quiet down considerably given the design and age of the locomotive. Even so, I’m extremely happy with how well it’s running.
The decoder is taped to the top of the motor housing:
The TCS M1s have a low profile. So, I could leave it in that location and still have enough headroom inside for the shell to seat properly. To finish the installation I’ll either use the above decoder with the 8-pin plug trimmed off, or get another TCS M1 with longer wires and no 8-pin plug.
Next on the agenda is to add front & rear LED headlights. I’ll probably go with 3mm warm LEDs but may opt for the SMT LEDs that I recently used for the front headlight installation in my Atlas S-2 switcher. After that I’ll have to decide how much modication I want to undertake to model it after a specific NYC H2
Congratulations on getting it working nicely! I have been following with interest. I don’t have any brass locomotives other than the scratchbuilt HOn30 critter in my avatar and its twin, still under construction. I have been very wary of buying brass given the apparent challenges of getting them to run properly. After seeing what you have done, I’m a bit more tempted to take the plunge with a similar engine. If it doesn’t work out then at least I can say that I tried.
You have stated a couple of times that you don’t think there is space for a sound decoder. I’m going to suggest that you reconsider. The Loksound Select Micro is very thin and tiny. It would easily fit in the space that the TCS M1P decoder occupies, and the so called ‘sugar cube’ speakers will fit in very tiny spaces even with an enclosure attached.
Here is an example. This is HO scale using a Loksound Select Micro decoder with two (yes - 2!) sugar cube speakers. This thing is 2 1/8" long. Please ignor the fact that the shell is not on straight. It is a friction fit so it doesn’t take much to move it out of place:
Here is some information on sugar cube speakers (also called iPhone5 speakers):
Note that sugar cube speakers must have an enclosure. It doesn’t have to be very big but it must be there, and sealed tight to the speaker. I make mine out of .040" styrene.
Also note that the way to get the best sound out of the sugar cube speakers is to glue the enclosure directly to the locomotive shell.
Thanks, Dave. You are correct about the Loksound Select Micro. When I was originally looking at a possible sound decoder install my initial thought was to place the decoder vertically under the drive shaft area on one side (where there is some availalble space) and a speaker on the other side. It wasn’t until I placed the shell back on that I realized I didn’t have the full width of the brass base (1.275") but only the width of the motor housing (0.800"). I thought that pretty much eliminated all the sound decoders I was interested in - i.e. Loksound and TCS. [:S]
Now after discovering that a low-profile, motor control-only decoder will fit horizontally on top of the motor housing length-wise, you are right that a Loksound Select Micro will fit there, as well. And having a 4-function decoder would be advantageouos if I feel like being daring and illuminating the colored lantern at the corners. I’ll think about tackling that one AFTER the front & rear headlights. [:P]
There are two “cube” speaker sizes (so far) that will fit under the drive shift and between the motor housing. There was a 20mm OD speaker that would have just fit but the enclosure, unfortunately, increased the OD to 22mm. [:(] Those where just from TCS so I’ll have to investigate some of the other manufacture’s speaker options.
Two questions for you, Dave:
You mentioned using two cube speakers - I’m assuming those are wired in parallel? Is phase an issue for speakers of that size?
Adhering the speaker - Wouldn’t silicone adhesive (e.g. DAP) work just as well as epoxy? The advantage is that it would hold well but be somewhat easier to remove than epoxy.
Thanks for the input, Dave, and for helping me realize that the Select Micro is still an option, if I go with sound.
I think the reason for epoxy is stiffness. There was an item I once came across in the web where someone experimetned with different materials for speaker enclosures. The more dense and stuff, the better - lighter weight materials flex with the sound pressure and become alternate radiating surfaces with lots of distortion. I think his best option was to make an enclosure from lead - very dense so the sound only came out where it was supposed to, with the added benefit that if you had to remove any of the loco’s weight to fit the speaker in, this added some of it back. A solid epoxy instead of a flexible caulk, when making the shell the enclosure, would I think help stiffen the shell and keep it from possibly vibrating.
If the speaker is already in a sealed enclosure, I see no benefit to attaching the enclosure to the shell with epoxy.
Since Selects user 4 to 8 ohm speakers, if these are 8 ohm speakers I’d parallel them for 4 ohms. Phase must match or the sounds will cancel each other out. Phase is always important, although theoretically one mosnter speaker and one tiny speaker out of phase might work because the volume of the small one couldn’t cancel all of the volume of the large one. Two speakers of equal size out of phase means you will get two equal but opposite sound waves which is not what you want.
It shoudl all fit nicely in there, that’s a HUGE loco compared to Dave’s - or remember Wolfgang’s little Grandt Line 23 ton boxcab with sound?
The space in the H20-44 - although bigger than Dave’s 23-ton boxcar - is actually deceptively smaller than it looks. A decoder and speaker must be no deeper than the short side of the motor housing because the interior of the shell just clears the long side.
There are also extended set screws on the drive shaft that force you to allow clearance as it rotates and screws coming up through the brass base plate to compete with floor space. Also, one of the interior brackets inside the shell (that line up with the red washers in the earlier photo) is twice as long on one side; thereby restricting the available space above and below the drive shaft even more. I might be able to remove the excess part of the bracket with a file.
So, while a Loksound Select Micro will work on top of the motor, any speakers are going to have to be glued to the interior roof of the shell to make it work. This means having to allow for enough slack in the wire to remove the shell but organized so that when the shell is seated any wires aren’t getting shredded by the drive shaft.
Sound would be fun but…it’s going to take some thinkin’ to make it work. [:S]
Randy has already answered your question, but, if you want to learn a bit more about wiring multiple speakers, go to the two links that I posted earlier.
Also, as Randy explained, phase is critical. Unfortunately the leads on most speakers are not marked with + and -. I use the physical location of the contacts on the speakers to keep the phase consistent.
Another thing to keep in mind is that the speakers don’t have to be in the same place. You can put them wherever they will fit and just run longer wires between them. Two speakers is not an absolute necessity. One will sound pretty good too.
As far as enclosure size, I use .040" square stock for the sides of the enclosures and .040" flat sheet for the back. It’s tiny but it works well.
As far as using epoxy vs silicone to mount the speakers I might be splitting hairs a bit, but the point is to get the enclosure firmly bonded to the shell so the sound is actually resonating from the shell itself. Again however, we are splitting hairs. If you don’t have space to glue the speaker enclosures to the shell you will still have sound. You might have to turn the volume up a bit but it will still work. Multiple speakers mounted to the shell is the ideal method, but not your only option. One other possibility might be to mount the speaker(s) on the bottom of the frame instead of inside the shell.
Could those screws be replaced with Allen head set screws? They would be tiny but they would work. The challenge would be finding the right size. NWSL sells metric set screws which I believe have Allen heads, Scroll down a bit:
If you are really brave, another alternative is to cut the heads off of the existing set screws and then cut a slot in the remaining screw shaft so they could be tightened with a jeweller’s screwdriver. You could cut them short enough that they end up entirely inside the drive shaft female link. Fussy but doable. I think I would use a little Loctite Blue on the set screws because you won’t be able to apply as much torque as you can with the bigger screw head.
Regardless of whether you modify the set screws or not, I would consider using some sort of restraint to keep the wires away from the drive shafts. You might be able to use some heat shrink tubing, or you could build ‘conduit’ out of styrene sheet to restrict the movement of the wires.
