I've been wanting to try out the Hobbytown Multidrive system for a long time now, but could never seem to find them for a reasonable price. Now that they're back, I couldn't help myself.
https://www.youtube.com/watch?v=UBrE2FHsOhw
_________________________________________________________________
Neat Darth! Never knew that such a thing existed.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
That is a pretty neat looking set up. Glad to hear your PAs are tracking better.
.
-Kevin
Living the dream.
A very interesting video, Darth. Are those Athearn BB PAs? Do the multiple in-line drive shafts make the multidrive system more susceptible to increased noise?
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
Interesting. What are the advantages of this setup?
- Kevin
Check out my shapeways creations! HOn3 and railroad items for 3D printing:
https://www.shapeways.com/shops/kevin-s-model-train-detail-parts
Wow! I never knew anything about Hobbytown. Nice video. Not to stray from topic, but your video on Acela couplers just helped me out.
I've gotta look at more of your stuff!
Mike.
My You Tube
Those Pittman motors will pull not only pull the tar paper off the wall, but take the wall with them. They are tememdously powerful. Sounds like a road slug, mother, road slug setup. Seems to work well.
msrrkevin Interesting. What are the advantages of this setup?
He states some in the video.
For Locomotives that came as dummy units anyway, this seems like a great way to go with Direct Current.
Are the helical gears arranged opposite from each other to cancel thrust (similar to arrangement of a herringbone gear, but separated by distance of wheelsets)?
Our club has an A-B-B-A set of these for our a train called the Emerald Rocket (known internally as the Green Slime). They must date back to the 1980s, if not the 70s, if not the 60s. The open-frame motors have been replaced with cans, so we were able to convert them to DCC. The epoxy that holds the body to the frame has worn out, but the drives are still going, and they will indeed pull the paint off the wall (and a very heavy passenger train up a 2% grade). Not bad for only two motors.
Oh, and the best part -- they are so noisy, we don't need to put sound in 'em! :)
tstage, the shells are from a set of Athearn BB PAs. It was one of the old sets with metals sideframes, and I could never seem to get the axles level in the dummy units. The Hobbytown trucks use 1:1 helical gears and don't contribute any additional noise beyond the metal wheels on the track, so all the running gear noise comes from the reduction gear tower and the motor.
msrrkevin, the main advantage is the increased electrical efficiency since there's only one motor. This doesn't make as much of a difference now as it did 50 years ago, but as the video showed, this entire 3-unit setup only draws 0.3A on average running free. I also found the slipping current is about 0.5 to 0.6A, and the stall current of the one motor is under 2A. All the open space in those multidrive units allows you to fit whatever you want inside without having any motors or drivelines in the way, so you could add tons of weight, or potentially fit smaller O gauge speakers inside for some great sound!
mbinsewi, I'm glad the video helped! I found later from a few others that Kadee NEM couplers are a drop-in for the Bachmann boxes, but the way I put it together allows closer coupling.
caldreamer, the old Pittman motors are hard to beat! I didn't use one in this project, but my Pittman powered trains are about as bullet-proof as you can get. The rewound Radioshack motor I put in this one has about as much torque as a DC-91.
BMMECNYC, This is actually a good option for DCC too, as you only need one decoder to drive the whole thing instead of having to MU 3 decoders. The helical gears are all arranged the same way and rely on thrust washers on each side. The chassis design has remained almost unchanged for close to 70 years, and it's still one of the most reliable on the market. There are certainly others now that are quieter and look better, but I have yet to see any that are as easily customizable or dependable as these.
BMMECNYC Are the helical gears arranged opposite from each other to cancel thrust (similar to arrangement of a herringbone gear, but separated by distance of wheelsets)?
Interesting, but I think that would actually cause a problem. As delivered by Hobbytown, the design will have both (or three, in the case under discussion) wheelsets thrust over to one side of the truck gearbox. And there will be no torque around the truck kingpin.
With a two axle truck, the herringbone idea described would have the wheelsets thrust to opposite sides of the truck. This would then offset the wheels and might cause tracking problems. Also, there would be torque around the kingpin, and this would twist the truck and produce side thrust on the rails.
With a three axle truck, the torque around the kingpin could be eliminated. But then the center axle would be thrust towards the opposite side of the gearbox compared to the outer axles. This would cause misalignment of the three wheelsets.
An advantage in the two axle truck would be that there would be no thrust on the truck end bearings. On a three axle, it would be lessened.
It would seem the ideal location for herringbone gears would be in the gear tower. Finding herringbone gears that small would be a challenge. And construction of the gear tower looks like it would be fun.
Something else to explore would be using tiny ball bearings. I think some O gage trucks have used them.
Ed
The gear nomenclature isn't correct.
This is a herringbone gear. The shape looks like a herring's bone structure.
This is a helical gear set.
Having worked in the gear machine tool industry for over 30 years I like to see the proper description used for the gears used.
You'll notice in the vidoe that the truck can be pushed and the tower gears rotate. Something that can't be done with a worm drive gear.
Bernd
New York, Vermont & Northern Rwy. - Route of the Black Diamonds
protolancer(at)kingstonemodelworks(dot)com
Bernd,
Note below that he used the word "similar". He was describing alternating right and left hand helicals, and used the word herringbone to try to describe that. At least, that's how I interpret his idea.
When I first used the word "herringbone" in my reply, I followed it with the word "idea", indicating that I understood his use of the word "similar". My later use of the word "herringbone" was in reference to herringbone gears, as you suggested.
Something I only now realized is that, by alternating left and right hand helical gears in the truck, it would produce contra-rotating wheels. My original impression was that the rotations would somehow "cancel out" and end up with all wheels rotating in the same direction.
But that ain't happening. So, if I understand it properly, his idea won't work. At all.
Darth Santa FeThis is actually a good option for DCC too, as you only need one decoder to drive the whole thing instead of having to MU 3 decoders.
But not nearly as versatile as 3 MUed decoders, plus you are stuck with a 3 unit set. No idea as to the cost of the hobby town drive, but a motor decoder can be had for less than $25. So for under $75 you can run 1, 2 or 3 units. It kind of goes back to whats important to you.
If you want to run an A-A set for fun, you cant easily.
What happens if you wanted to run a ABBA set with hobbytown drive, will the asymetrical loading of the drive line become an issue?
That having been said, I do have a yellow box dummy Gp7 or 9 laying around that sounds like a ideal candidate for a hobbytown drive.
7j43kMy original impression was that the rotations would somehow "cancel out" and end up with all wheels rotating in the same direction. But that ain't happening. So, if I understand it properly, his idea won't work. At all.
Yep,
Didnt think that one all the way through. Posted before the first cup of coffee.
7j43kWith a three axle truck, the torque around the kingpin could be eliminated. But then the center axle would be thrust towards the opposite side of the gearbox compared to the outer axles. This would cause misalignment of the three wheelsets.
Not sure about now, but the original drives had dummy center wheels (darths video of buildng a PA kit shows this.
Back in the olden days, Hobbytown made two versions of the E7's. One had a DC-90 motor and non-driven center axles. The other had a DC-91 and all wheels driven. I'm not sure which came first and/or if they were concurrent. What they did for multi-drives, I don't know.
I wonder if Hobbytown did the same for the PA's.
Incidentally, my RSD-5 had/has all wheels driven.
I,too, was smitten with the Hobbytown multi-drive system. At that time in my life, I didn't have the money to pursue the concept.
BMMECNYCBut not nearly as versatile as 3 MUed decoders, plus you are stuck with a 3 unit set. No idea as to the cost of the hobby town drive, but a motor decoder can be had for less than $25. So for under $75 you can run 1, 2 or 3 units. It kind of goes back to whats important to you. If you want to run an A-A set for fun, you cant easily. What happens if you wanted to run a ABBA set with hobbytown drive, will the asymetrical loading of the drive line become an issue?
The powered chassis is $65 and the multi-drive chassis is $45, or you can get a power-multi combo for $100. The multidrive is intended to be a permanent coupling, so you only use it when you want to keep a set together. Otherwise, you can always go with the individual units.
From my testing so far, the torque on the driveshaft can derail the center power unit when the front unit is stalled going forward, or when the rear unit is stalled in reverse. I haven't added any weight though, so making them heavier (especially the power unit) should help with that. For an ABBA set, I would do 2 sets of 2 units instead of 1 set of 4, otherwise you'll have a "dancing queen" jumping the rails due to all the torque in the extended driveline.
Darth,
I'm looking forward to hearing more about your adventures with this beast. Or beast-ess, perhaps. I'm kinda envious (in a good way), but it's not like I don't have plenty of projects to play with.
Darth Santa FeFor an ABBA set, I would do 2 sets of 2 units instead of 1 set of 4, otherwise you'll have a "dancing queen" jumping the rails due to all the torque in the extended driveline.
I wondered about that, and also get the reference. Well punned, sir.
Never heard of multidrive. An I missing something important?
Rio Grande. The Action Road - Focus 1977-1983
EdslandVery cool, I really miss Hobbytown back when they where in business I was more into the RC planes and didn't get into trains till later.
They actually are back in business with most of the classic kits and drives available, so I've definitely been having some fun with all that!
http://hobbytownofboston.com/