Best Of The TP56/TP70 Kitbash thread N scale

[C855B]

... You do have to remember that there's only two of these things, it's not like they are all over the place, and if/when they build more it probably will have additional changes as well. ...

Exactly. When you're in the business of building "new" locomotives out of recycled parts, every unit is custom in that you use what you have on hand. This was/is the problem with modeling NRE Gensets, where each product is constructed out of what happens to be sitting in their breaker yard in Mt. Vernon (IL) at the time. There are similarities between units, of course, but the devil is in the details.

[randgust]

I got in David's HT-C sideframes from Shapeways tonight.

Wow.  That's not FUD, the resolution is better than FUD and it's flexible.   I'm really impressed.  Haven't cleaned it up yet and there's some sort of residual oil on it.

OK, you could make a gearbox out of this stuff.   I can also see that if you're trying to make a master, THIS is the stuff you'd want to use because it could probably stand up to having the mold pulled off of it without damage.

Pretty busy tonight but I can file down the Roco frame and put this one on it pretty easily.

Not to completely mess up what we're discussing....but it did occur to me that Atlas does a whole lot better job of keeping parts around than Kato.  They have the SD60 truck.  David, what would it take to re-arrange this truck with a different gearcase frame to put the drive gear on the end?   Using the original gears, axles, etc.... just a different case....?     Hey, you convinced me you could probably do this from Shapeways.

http://shop.atlasrr.com/p-3653-sd-60-truck-assembly.aspx

[dcutting]

I got in David's HT-C sideframes from Shapeways tonight.

Wow.  That's not FUD, the resolution is better than FUD and it's flexible.   I'm really impressed.  Haven't cleaned it up yet and there's some sort of residual oil on it.

OK, you could make a gearbox out of this stuff.   I can also see that if you're trying to make a master, THIS is the stuff you'd want to use because it could probably stand up to having the mold pulled off of it without damage.

  Glad you like it. I would just print off all of the gearboxes with this stuff... masters just turn into a huge mess with this kind of intricate part.

Not to completely mess up what we're discussing....but it did occur to me that Atlas does a whole lot better job of keeping parts around than Kato.  They have the SD60 truck.  David, what would it take to re-arrange this truck with a different gearcase frame to put the drive gear on the end?   Using the original gears, axles, etc.... just a different case....?     Hey, you convinced me you could probably do this from Shapeways.

http://shop.atlasrr.com/p-3653-sd-60-truck-assembly.aspx

I respect the "let's use what's already here" approach, but even if you could cooperate with atlas on getting more spares or whatever this becomes a serious issue when lots of people want one. I'm also considering taking this approach of designing around Rapido's parts to models such as the C415 and C636, just changing the gearbox shape. So for me it's more of a forward-looking approach. So while I could do that, I think the smart forward-facing hing to do is to source new parts.

David

[up1950s]

Well, the arrival of the vintage Roco E7 truck confirmed my suspicions.  It may be vintage, but parking that worm over top of the rear axle produces enough room to jam a universal in there and it looks like everything will fit.  Those old Roco universals are a POS, but they can be trimmed and polished to work.  I've put just the horn on one end of the shaft and the cup on the other.  Given the torque of the gearhead, wheel wipers don't bother me a bit. 



Interestingly enough, there's a slight downward force on the wheels due to the wipers, it actually equalizes.

I'm going to design this with the worm under the cab and the motor in the nose, and pack all the lead in the cab end.

The wheelbase is right on and different sideframes will be easy.   If the deep flanges bug you the wheels could be turned, I'm using Peco C55 so not an issue.

Do all wheels PU and drive ? Is there any TTs on the other side ?

[randgust]

It's distantly related to the original Roco / Mehano vintage six axle truck in that 2 axles are powered (under the gear tower and center) and the 'inner' third axle is free-rolling, only the two outer axles have a pickup.    It's unlike it in that it has steel instead of plastic axles, far wider and more durable gears, the idler axle actually rolls freely despite the pickup wipers, it has a rather mild equalization, and there are no traction tires.  It's no Kato but it's no Yugo either, and if it shares any parts with the Roco F7/GP I can't see that either.   I had one of the E7's back in the 70's and it was really a pretty nice unit, probably the best they ever designed.   I actually used one of these chassis to repower a Lima FP45 and make a pseudo-SDP40F out of it.   It didn't look right, but it ran pretty well.

I was thinking about bending the wipers back around to pick up the center axle (which is what I do on the old Mehano drives) but in this case I think I'll just solder on another wiper.   Because the gearhead is involved, I'm not particularly worried about either slow speed or torque issues that are usually a concern with pickup wipers.   I was pleased to see the wipers exerting enough flexibility to equalize that wheelset just a bit for better electrical pickup.    I am somewhat concerned about the idler axle, which is why I put the tower end under the cab and load that cab end up with lead and have the light hood/nose end above the idler.   

I started filing off the E-unit sideframes last night to replace with David's slick HT-C ones.    I'm not going to get really enthusiastic about this until I get it running and test it.   I'm going to shorten up the universal like I did on my original Heisler build, everything should fit.   Getting the gearhead to link up with the worm shaft and keep it short enough is the real challenge here, and until I get past that part... hold both fire and applause.

I'm not saying this is the only way to do it, but having tried all manner of critter drives over the last decade, I'll bet on this approach without spending either too much time or too much money getting a decent-performing result.   I've pretty much convinced myself I can make anything move, but six months after it's done the question is will I actually USE IT for operations, and about half of my tiny critters flunk out on that evaluation because of poor pickup, poor performance, or constant fiddling with the mechanism.    My best idea that didn't work for crap was mounting a tiny Motorola 9v pager motor on a Tomytec 4-wheel truck with offset drive to repower the GE 25-ton; I got it to bench-test fine and all was good until I actually ran it on the layout.   Really had to horse it to get it started due to lack of torque, and then as it got moving it launched like a rocket and was essentially uncontrollable.   Life's lesson was use bigger motors or a gearhead: pick one.

[up1950s]

 That shaft through the worm can be removed and the coupling on it can be convinced to come off , fly across the room hit the array of video equipment , ricochet quite a few times in rapid secession , then lay up somewhere yet un-spied . ( edit .... found )
 I plan on coupling the gearmotor and worm shaft as Randy says but getting the two to snuggle up a bit more knowing that the truck and gearmotor will not swivel .
 I ordered the Max inspired Gizmoszone 12 VDC MGH1015-B .http://www.gizmoszone.com/shopping/agora.cgi?page=gearmotor4.htm and http://www.gizmoszone.com/shopping/agora.cgi?cart_id=76583856.428439&next=20&ppinc=1g&product=Gearmotor
 I plan on using the Bachmann Plymouth WDT shell and the Atlas SD-9 type sideframes .
 Center axle will be not aligned but I will live with that as I don't know of a option .
 If the flanges are reduced , and the wheels and sideframes painted a flat black it will un-highlight the slight mismatch of the center wheel and the sideframe journal .
 I plan on using the Bachmann Plymouth WDT ( 3 axle ) critter , though I will probably need to extend the rear half wall area a bit to fit the MGH1015-B .

I know this is not a TP56 , but the DIY use of a prototype C truck under a critter has ideas and info that strict TP56 builders might benefit from .

[up1950s]

Found this http://www.tycoforums.com/tyco/forum/uploaded/JRG1951/20150102194258_HTC_Switcher.jpg

Also thought of using a DD40AX truck from the middle run Plus/Sprectrum line . It has a removable truck - sideframe and gear tower . I was thinking lopping off the outward most wheel right where the gear tower begins . It then would leave the odd wheel spacing of a C truck with all axles powered . But then the stainless rule was used and a C truck has about a 13'6" outer axle to outer axle span , and the modified D truck comes in at 11'6" . FWIW that's the span of the Bachmann Plymouth OEM axles .

[JanesCustomTrain]

Found this http://www.tycoforums.com/tyco/forum/uploaded/JRG1951/20150102194258_HTC_Switcher.jpg

Nice find. Make it a bit more modern and use an Atlas MP-15 shell instead.

Jane

[Catt]

The drawings on the TYCO forum show that this could be done in both N and HO.I think I just added two more projects to the pile I can't see the top of now.

[up1950s]

See the Weekend Update this week , The TU-TMC100 is a very close match for the outer axles of a C truck .I may go that way as there is more room for weight .

[randgust]

Kato motor, gearhead, universals all fitted up last night and 'finger tested' under power.  Everything is going to fit as planned, have to do a height check though and secure the motor down.

Would have had a photo up but had two hours on my hands and knees searching for the gearhead pinion when that fell out and rolled across the floor.   That's smaller than a grain of rice and about the same color on a patterned white adhesive tile floor. 

Before I go ahead and scratchbuild a body - anybody seriously doing one in RP?  The TP70 is marginally bigger than the TP56, that's the way I'm going as a slightly bigger body is critical on something this tiny. 

[u18b]

I can't wait to get back to this project.

Hopefully I'll get my order form Japan soon.

[randgust]

Well, go Ron...!  Just remember, your original 44-tonner concept on the 11-105 is what got me started in all this crittermania.   OMG, that was like what....12 years ago now?

What's slowed me down is that I'm a lot fussier now on the difference between making it move, and making it work well.  Got completely spoiled on how nice and reliable the 11-105 chassis are with a different motor on it and anything less seems like a sellout now.   

[u18b]

Yes, Hard to believe it was that long ago.

That 44 ton thread was a classic.  And I'd like to think that we were somehow responsible for it being mass produced years later.

We showed it could be done.

Atlas then explored doing one with the Chinese.... built ended up declining (probably because of scale hood width issues).
And then Bachmann picked up the project.

Hey!  Who knows where this thread will lead.

[dcutting]

Before I go ahead and scratchbuild a body - anybody seriously doing one in RP?  The TP70 is marginally bigger than the TP56, that's the way I'm going as a slightly bigger body is critical on something this tiny.

I can set you up with the body... just get me the dimensions and I can put something together from the geometry that I already have created.