ALCO RS3 - Atlas vs. Weaver

The Atlas version is oversized. Put the Atlas & Weaver RS3 side by side and the difference jumps out at you. The Atlas my be 1-43 scale. The Weaver model great.

I have two.

My opinion the twin can china drives of the Atlas are bullet proof runners; especially once rewired. That said the car body suffers from the size needed for the vertical motors. It's basically wrong, too big and "cleared for take off" with the usual see through chassis gap over the trucks. Also the side-frames suffer from the EMD like stanchions attaching to the outside of the side frame instead of the prototype's top of the deck.  Not a model I would attempt to super detail.

Conversely the original Weaver has a comparatively GREAT scale car body made more so with the detail candy P&D sells, but the drives are glass jaw weak. I cannot to speak to the final version of the Weaver's having never purchased one, but if they're like the RPC made Weaver Fa's.... yuk.

Early Weaver used non- aged plastic for the gears.  They all split as they shrunk.  I think Weaver was willing to replace them.

Interesting on the Atlas - do you mean that it is larger overall, so we 17/64 freaks ought to get one, or just the hood is too wide?

i have a Weaver with the old single motor. It will pull the walls down but it takes 3-4 amps to do it. I do not have the Atlas RS3 but do have their GP15 that runs well at 1/2 amp or so.

I have a bunch of the old single motor weavers, most have some PRR specific details added.    I like the single motor drive.   I do not like 2 motor drives.   they always seem to run jerky to me.   

I think the Weaver 2 motor drive RS3 sits too high on the trucks too.  

I do not have an Atlas RS3, but their RS1 looks oversized to me.

I really like my Atlas.

I own 4 of the Weaver RS3. All have had their drivetrain modified to dual tower drives, which not only increases torque but takes strain off just one tower. On most of my units plastic railing details have been replaced with brass for durability. All have been weighted for traction. the truck bolster-sideframe interface has been modified to allow greater equalization action, which helps a lot over the myriad trackwork at our club.

they run great, a couple have had larger lower gears installed for superior low speed characteristics. I usually run them in pairs, MU'ed to a single 4 amp decoder.

all this took some work, but it's a process I enjoy doing.

A review of the RSD 4/5 indicates that it is 3 scale feet[3/4 inch] too long, I don't know if this applies to the RS3 also but a posting a while back stated that size discrepency was brought up to the late Jim Weaver when the model was first produced and he acknowledged the issue but indicated that if Atlas did not market the model the factory would repackage for another importer. I guess being a Tman loco they elected to sell it despite the accuracy of the model.

Back when the model was first produced Sanda Kan did the tooling and built for a number of importers,I would not be suprised that some of that tooling was used on a number of orders. The Atlas Tman PS-4750 covered hopper appears to be a good example of a scale body shell with some very thick moulded ladder and end framing[available tooling from another project?] JMO 

Many thanks to all for their input, especially for the posted photos.

As usual the choice seems to devolve into a 6 of 1, half dozen of the other proposition, with no one entirely satisfying option available. Perhaps in recent years the detail and accuracy bar has been raised so high that these models, which were developed quite a few years (decades?) ago can not measure up to expectations. Yes one could modify, detail, repower, etc, but if the hood is too tall, or too long, or too wide it still wouldn't quite cut it. For me at least. I still remember the disappointment I felt when I found out the old Athearn HO GP-9's had an overly wide hood to fit the motor: talking about the circa 1960's models here. Anyway, with my luck if I went ahead with one of these RS-3's, someone would announce their new 3D printed version a couple of months after I finished. Think I'll stick with an EMD roster for the time being.

My preference is for the single motor Weaver as it is the only mass produced RS3 whose body dimensions are accurate for 1/48 scale.  Weaver single motor drive RS3's initially were produced with an enclosed center tower reduction gearbox. These came in a red box.  Later production single motor RS3's (black box) were fitted with a engineering plastic chain driver tower at one end and a long through the fuel tank prop shaft.  The change may have been related to enabling the 3 rail version to negotiate tighter curves as Weaver's marketing was shifting toward 3 rail.  The early center tower version had high failure rates due to split pressed on axel gears as previously noted. I had 2 units and the gears split on most of the axels within 3 years.  Bob Weaver would send me free replacement axels but several of those failed as well.  Fortunately reliable replacements were offered by NWSL and P&D. 

Bowser/Cal Scale offers beautiful lost wax brass handrail sets, fan covers, horns, and PRR trainphone antenna sets.  Carving off the cast on hood handrails and replacing them with wire ones further adds to prototype appearance.  With the replacement geared axels, added weight, and a flywheel on the Pittman motor Weaver single motor RS3's can be upgraded to excellent runners. I might add that due to the split gear issue these models can often be had for around $100 or less at train shows.  For those that like to work on their models, the Weaver RS3 makes for a great fixer-upper.

Ed Rappe 

On the 3 amps, early Weaver used the non- rare earth magnets from Pittman.  You can reduce heat and current draw significantly by simply substituting the more efficient Pittman.  I forget the exact motor number, but Pittmans are 8x1y or 8x2y, where x and y are related to pin- outs and length.  The 2 means rare earth magnets - a giant boost in performance.  Weaver was trying to save a buck and a half per model.