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I dont want to hijack this thread but it sounds like we've identified this drive (I think) so I have a similar question.  Does anyone have any experience or knowledge about the NWSL magic carpet drive (believe that's the name) that has been advertised heavily the past few months in most of the model train magazines. Says it's back in production so it was offered before.

 

Each axle has its own motor just like traction motors on the prototype which would leave tons of room inside the shell just like this RS2/3 drive shown above. But, although it looks great and leaves room inside the shell how does it operate? Anyone ever seen it operate in the real world?

 

Butch Holtgrieve 

it's also very similar to the drive Sunset used in their RDC model, and I believe the Brill 660 gas-electric as well.

 

Butch, the Magic Carpet drives had a tendency to 'cog' at very low speeds, plus the open gear train can be exposed to picking up bits from the track. I haven't tried them yet, but I understand the new design for the Magic Carpet may have addressed both issues, since the design was changed.

I recently picked up one of the SS 660 Gas-Electrics.   As you say it has a similar drive.    The car will pull itself and 3 other cars on level track.   Up a grade, 3 freight cars.   considering that it has one dummy truck which is carrying half the weight, I think it pulls pretty well.    For the moment I am being cautious and do not want to overload it.

The weak drive prone to cogging maybe due to a poor design choice on the motor.  Replace it with a well engineered high torque coreless motor with rare earth magnets.  Coreless motors do not cog and have very, very low starting voltages with high torque.  I've recently done surgery on a custom built kit bashed Thomas engine.  The frame was from a samhongsa 0-8-0 cut down to an 0-6-0 while the body was a diecast push it around model from the UK.  Anyway the original gearbox and motor finally gave up.  It tended to stall and cog (inexpensive china motor) but ran decently given enough juice.  I replaced the mechanism with a BB NWSL mod .5 gearbox and a surplus 2342 Faulhaber motor.    Anyway the point of the story is that the new rebuilt drive will run around on as low as a single AA battery.  

 

I've run both the similar RDC drive and the magic carpet the latter is weaker and ideally suited to traction.

Obvious pro with this arrangement is the amount of space left available for speaker, battery, or detail.  With this drive, one could do a model like that rs-2 in the Chicago meet contest photos, with engine compartment modeled open, and have it still be powered.  And the cab too.

 

Potential cons with this arrangement include gear ratio, gear noise, lack of flywheel, power, and motor control.  The first three are somewhat similar to issues with the standard two-motor china drive, due to the lack of room.  The power issue is due to difference is the size of the motors being utilized.  Motor control at lower speeds with two motors will always be difficult with DCC due to multiple back emf signals confusing a decoder.  Or require a lot of electronics with DCS or Lionel.  I think.  I'm way more familiar with DCC than either DCS or TMCC/Legacy.

 

Like anything, the particular application will probably play the biggest role in success or failure.  I know the original magic carpets were ideal for traction models, typically only powering a single car.  Not so good for bigger locos and longer trains.

 

What I personally dream of building is a drive that utilizes the fuel tank and the volume between the frame beams, but below the walkway, for a speaker and drive components.  Only a single larger motor would be above the walkway.  Ideally a gear motor, for reduced speed and noise at the truck gears, and a flywheel for smooth operation.

 

Jim

Years ago I owned a Key RS3 with this drive.  It ran ok - but noiser than the improved mid to late production Overland/Ajin drives (forget the early ones!!)  A disadvantage of this configuration is not having room for flywheels to smooth things out.  To my knowledge Key never imported any other diesel with this drive.

 

Ed Rappe

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