Minitrix U28C and U30CG wheelsets

[nickelplate759]

Since no one bit on my offer to sell my ancient Minitrix U28C, I've decided that means I should resurrect it instead.  Since it looked silly by itself (I have no other Santa Fe engines), I've acquired a U30CG to keep it company - eventual plan is to have them pull at 1960-ish Santa Fe passenger train like the Kato El Capitan.  I'm not too interested in 100% accuracy here, neither in the consist nor in the engines (good thing, since the U30CG is too short).

First order of business is getting the wheels into shape.   They won't work on code 55 as is.   NWSL sells replacement geared "Minitrix Diesel" wheelsets - I believe these were intended for the F-units.   I'm hoping I can use 4 of these for the 4 geared wheelsets , and then a pair of NWSL ungeared wheelsets for the inner dummy axle.  Does anyone know if they  U28C and U30CG use the same wheelsets as the F units did?

[narrowminded]

I could likely turn those flanges down if that would help.   

[nickelplate759]

Thanks for the offer;  I probably could too, but I'd rather replace the wheels. Plus the plastic ungeared wheels look terrible.
<edit>

I also don't want to just put them on a Kato chassis.  John Sing did that - beautifully, but I want to keep the original chassis.
Here is Mr. Sing's photo spread on how he did a U30CG on a Kato chassis:  https://pbase.com/atsf_arizona/santa_fe_u30cg&page=all 

</edit>

[nkalanaga]

As far as I know they did.  And if not, turning the wheels is REAL easy. 

I did it (on a half-dozen Fs) simply by pushing the insulated wheel against the gear, chucking the now-exposed axle in a Dremel, and using a needle file.  Eyeballed the flange, checking it against an NMRA gauge now and then.  Then regauge the wheels.  They ran fine, on Railcraft/ME code 40 flextrack,  for 20 years after that, and will still run, if I wanted to run them. 

Once nice thing about those old Minitrix engines is how simple the trucks are.  I was constantly having to clean the cat hair out of mine, but it only took a few minutes to do a 4-unit set.

That won't solve the plastic-wheel problem, but some silver paint might work there.

[randgust]

I can confirm that everything under the hood other than the frame casting itself is identical.  The front cab edge on the U30CG frame is more 'tapered' to fit, but the motor, trucks, driveshaft, everything else is the same.   I had a total of eight of them to make my fleet of six-axles including F45's and SD45's back in the day.  IHMO those were the best chassis out there for pulling power and reliability until Kato came along.

The idler wheels are just there for the ride, I'd think anything else would work in there with an acceptable axle diameter.  I just painted mine.   It's like getting rid of the milk-bottle windows, that's one of the easiest fixes of all time on an old Trix unit.

I ran mine hard - all of them - to the point where the plating wore off the wheelsets, and then the pulling capacity increased dramatically.  They'd equal any other six-axle SD I had.  Concentrating the weight on 4 wheels works just as well as six.

The idea of pushing the insulated set up to turn the flanges in a Dremel is freakin' brilliant, that would work on a lot of situations - thanks for that post.  I've done a lot of split-axles that way but that's a different solution for non-split.

I have two surviving Trix shells, both are on earlier Kato chassis.    I made a custom proper full-length fuel tank for my U30CG and have them available as resin castings.   If you want to preserve one as an N scale artifact that's fine, but you can make one into a proper locomotive if you want.



I'll never forget the one that the late great Jim Fitzgerald made - the Cotton Brute - with depleted uranium weights that set single locomotive pull records on Ntrak for years.   Shows you what the trucks can take anyway.
https://model-railroad-hobbyist.com/sites/model-railroad-hobbyist.com/files/users/JeffShultz/Brute_comp.jpg

[nkalanaga]

I've heard of the Cotton Brute, but don't remember ever hearing why he made it.  Just for fun?

My method of turning the flanges was mostly desperation.  I didn't have a lathe, and wanted smaller flanges, so this was the only way I could think of.  The original wheels worked fine on code 55 flextrack, but I had installed some code 40, and they didn't like that.  A four-unit set of Fs, wired together, was my main power for years.  With a coal/wood stove, track oxidized quickly (no telling what the air did to lungs!), and cleaning wheels was a constant chore.  32-wheel pickup minimized cleanings, and the truck design made cleaning easy.

[randgust]

I remember reading about it in the NMRA Bulletin, sometime before 1980.   Jim was one of the great early advocates of Ntrak, and I think this was purely a demo and crowd pleaser and you can read some pretty absurd stories about what it could pull - something like over 1000 55-ton MT hoppers.   I can believe it because on my friends layout he regularly ran a 100-car train of those behind one Con-Cor 2-8-8-2, 1% grades, and 24" curves.

This kind of punishment is how the RDA coupler came about, he found a way to lock the MT couplers and prevent vertical separation.  That's now an MT design standard.  So this became somewhat of a rolling lab rat we owe a debt to.

[cfritschle]

I replaced the two idler axles on each of my Minitrix U28C locos with the metal wheels from a Minitrix dummy F unit.  I also added a wiper so the idler axles provided some electrical pickup.

Wow, that was more than 40 years ago! 

[nickelplate759]

I replaced the two idler axles on each of my Minitrix U28C locos with the metal wheels from a Minitrix dummy F unit.  I also added a wiper so the idler axles provided some electrical pickup.

Wow, that was more than 40 years ago!

Perfect - that tells me that the Minitrix F7 and U28C did indeed share the same axles.  Thanks @cfritschle !

[nkalanaga]

Randgust:  Thank you!  I had wondered what it was for, as I never could see the point.  Two or three regular units would do the same job, and be more prototypical.  I'll bet that, if he could have made it in 1:1, the UP would have bought a dozen!

[RRRover]

"I've heard of the Cotton Brute, but don't remember ever hearing why he made it.  Just for fun?"

When I was a 10-year-old kid I was around at the birth of Ntrak and the Cotton Brute. Much like train races and other fun things (remember - the object of the hobby is to have fun!) there were competitions for pulling power, much like tractor pulls! A special section of track with a large gap in the middle and two power packs, one for each side of the gap, allowed two units to be coupled across the gap. Only a single unit was allowed on each side. Power was applied on both sides simultaneously and the unit that pulled the other across the gap in a tug-of-war match won! Needless to say, Jim's Cotton Brute was mostly a winner.

So the short answer was Jim built it for fun.

Rrrover

[peteski]

"I've heard of the Cotton Brute, but don't remember ever hearing why he made it.  Just for fun?"

When I was a 10-year-old kid I was around at the birth of Ntrak and the Cotton Brute. Much like train races and other fun things (remember - the object of the hobby is to have fun!) there were competitions for pulling power, much like tractor pulls! A special section of track with a large gap in the middle and two power packs, one for each side of the gap, allowed two units to be coupled across the gap. Only a single unit was allowed on each side. Power was applied on both sides simultaneously and the unit that pulled the other across the gap in a tug-of-war match won! Needless to say, Jim's Cotton Brute was mostly a winner.

So the short answer was Jim built it for fun.

Rrrover

Having access to depleted Uranium, didn't hurt his fun build either. 

[nickelplate759]

So my U30CG just showed up, and I'm having second thoughts about my approach.  The geared axles have sleeve bearings on the axle - one on each side of the gear.  The sleeve has an OD of about 2.15 mm.   The axle itself has a diameter of about 1.2mm, as does the ungeared axle (the one with the plastic wheels) which has no sleeve.   

NWSL has a geared axle set labeled as for Minitrix diesels, #7440-4, and the gear itself seems right (12 teeth), but the axle diameter is listed as 1.5mm.  At $40 a set of 4 I don't really want to buy them and discover they don't fit.  Anyone have any experience with these?

[C855B]

Having access to depleted Uranium, didn't hurt his fun build either. 

DU was just for the cred. DU's density is 19.1g/cm³; tungsten is denser, 19.3g/cm³. Both are equally difficult to machine, with DU's added benefit that the shavings can catch fire if you're not careful. Plus, it burns like magnesium, water just adds to the fun. 

[nkalanaga]

That was one of the problems they had building the first atomic bombs.  Working with uranium is NOT fun, and the radiation is the least of the problems.  Even enriched uranium isn't radioactive enough to cause problems during short exposures.  It can safely be handled, and carried, like any other metal. 

Prolonged or repeated exposures, on the other hand, can be a problem.  There were news reports a few years back about people developing cancers in or around their eyes, traced to WW II surplus military binoculars.  It seems that one of the lens coatings contained raw (natural) uranium, and after using the binoculars often, for years, the radiation caught up with the owners.

Depleted uranium is even less radioactive than raw uranium, so there would be even less danger.  Machining it would be the biggest problem.  As Mike said, it WILL catch fire!