MTH 3-2 CONVERSION KIT

In my opinion, starting with a 3-Rail version and changing out the wheels with the MTH "conversion set" is the wrong way to go, as you STILL end up with that swinging pilot and short hand railings. The 3RS modelers seem to prefer purchasing the 2-Rail version (which has a fixed pilot AND full length hand railings), and then change the wheel sets to "Hi-Rail wheels", if those are really necessary, and installing the 3-Rail electrical pick-up rollers.

Dear Hot Water,

Thank you for your thoughts.

I will wait to purchase the elusive Monongahela and Lehigh Valley 2 rail scale wheels version.

John P.Dunn Sr

John, I will keep an eye out for you. I wish I had bought more of them but they all came out so fast. I had stock piled others and sold some. I regret that. I had a rare to me CSX SD70ACe in 2 rail that I let go of. Luckily, they just got re-released with PS3. So hopefully my pre-order gets to me. 

 I had 2 of the NS NKP 2 rail models as you may have known, and the other one I also let go of. I now have none. So I'm hoping for more re-releases down the road. Just slowly MTH!! I'm not rich!

I have done many conversions with varying success. I cast my own pilots. They were flawed and got progressively worse. I hope the 3D printing process gets more refined and less costly.

 The best conversion I did was simply to get a different road's 2 rail model, and swap out the key parts like pilots and handrails. Painting a hand rail if necessary is fairly easy.

 If you can only get the 3 rail version, maybe I could assist down the road. I would suggest trading parts with someone you trust who also needs to convert (to 3 rail).

Without looking at other MTH units.  The Russian Decapod is a 3/2 offering.   Note that left and right wheels are isolated/insulated from each other, necessary for 2 rail operation.  I guess the three rail flange is assumed to operate on two rail.  There are no smaller flanged wheel sets, unless you order a two rail model.   Conversion involves removing the third rail pick-ups from the tender.  There is also a 3/2 switch on the tender.

Tender truck insulated side frame and wheel insulation pictured.

Three rail pick-up and axle pick-up, long copper strips that ride on the axles.

Removal of the third rail pick-up. Reassemble after the pick-up roller is removed.  Front truck on the tender is left rail.  Rear truck on the tender is right rail.   Note that the axles are/or should be, properly installed for two wheel/axle pick-up  Again note the insulation bushings, wheel sets pictured.

Three/two switch and another switch to reverse polarity.   I assume this is a conversion to two rail DC. 

My observation, I'm a three rail operator.  Best to contact someone who has done a two rail conversion with one of these locomotives/units. Three rail Wheel flanges would be a consideration, as I mentioned the decapod has larger three rail flanges, not both.

All other axles/wheel sets on the locomotive are insulated left/right.  Checked with an ohm meter.

John, By far the wheel swap is the easiest part of the conversion.  As mentioned by hotwater and Joe I would be inclined to wait it out, but also do like Joe suggested and keep an eye out especially for someone would might trade you parts.  I've done the parts swap method as well, pilot, handrails, etc... too and they by part turn out the best.  The 3d printed pilots are nice but not available for all MTH locos. Also require a little more work in terms of preparation and painting.

If you search you can find the 3 rail models

https://mthtrains.com/20-20281-1

Monongahela

There's a big list on the MTH search page for the Lehigh Valley in 3 rail

https://mthtrains.com/20-20281-2

click on the find it now button