MTH 3-2 conversions on 2-rail track

I ran a Hudson a couple times around my .148 rail test loop before I converted everything to 2-rail standards.  It worked just fine, even through an Old Pullman curved switch.

This is a complex topic actually. If you want to take High-rail steam and run it on Atlas 2 rail track you will have problems. Unless you use something like Ross or Gargraves 2 rail High-rail track it isn't going to work well. Atlas code 148 turnouts won't allow the High-rail engines to get through the flangeways. The wheels are too thick, flanges too deep, and they are not gauged to NMRA standards. If you are starting with a Scale Wheel model then everything will be fine on most 2 rail track.

The High-rail  diesels are easy to convert. Just drop in the Scale Wheel kit, remove the rollers, and flip a switch. That's it. If you want fixed pilots and full length handrails you will want to start with the Scale Wheel models which obviously don't need conversion.

I have done a lot of testing over the years. I even tried to build a 2 rail high-rail layout at one point so I could run my MTH Hi-rail steam on it. Frustration ensued...

My conclusion is that you need to chose one or the other unless you don't mind the look of Gargraves or Ross 2 rail track. I would suggest selling everything and just going to 2 rail scale wheel models. Your 3 rail rolling stock won't work on 2 rail track so that will all need replaced or converted anyways. MTH scale wheel engines will run on tighter radius than they list typically. I have run a 4-6-2 and 4-6-4 on 27" radius without a problem. Your 0-6-0 will likely run on 18"-21" and the 2-8-0 would be about 24"-27" if I had to guess.

MTH really didn't do Proto 3/2 the right way IMHO. They should have given the Hi-rail steam models code 172 wheels that were properly gauged. Then you would truly have an engine that could go from 3 rails to 2 rails and back again. As with so many things MTH does, they got 9/10ths right and messed up the most important 1/10. So unless you like the crap look of 2R High-rail track you are out of luck. Your High-rail Proto 3/2 steam engines aren't going to work on Atlas track. Unless you plan on having zero turnouts I suppose.

The Russian Decapod is 3/2  Here are pictures.  Locomotive drivers are isolated, as is the pilot truck.  Tender trucks are left rail right rail pick-up.

The 3-2 Hudson did not have.172 wheels, but made it anyway on my loop, which admittedly is 70" radius.  I could not stand the undersize cylinders and the look of the flanges, so made a new frame and cylinder assembly and converted to .172 treads all around.  Much better looking model.  Will not go around a 48" radius any more.

But if your desire is 2-rail and good looking track, convert. Get Joe to do the drivers - the rest is trivial.  If you want to keep DCS, do not change polarity in the locomotive.  I kept DCS, and am still trying to get a factory reset without having to buy a TIU.

I don't understand why MTH did their tender/locomotive pickup locations backward. Seems to me, it might have been more practical to insulate the locomotive and do all the pickup in the tender since that's where the electronics reside anyway.

As for resetting the locomotive, I'll let you know when I'm coming down your way and will bring my gear to reset/re-flash your Proto-2 locomotives for you.

Thanks for all the input and comments so far. So another question arises: how many of you run full 2 rail scale steam with blind drivers in the middle so you can have smaller radius curves?

Recently took delivery of an MTH  2 rail N&W J 4-8-4.  detail is ok but the electrical pickup is horrible.  The 3 axle plunger pickups on the left side of the engine do not function reliably and the engine stutters and stalls frequently.  N£W Chris reports similar issues with his  MTH J's and A's, as does John Sethian with his MTH PRR steam.  Both have altered the MTH 2rail pickup in various ways and now are pleased with performance.  When I get around to it I'm going to is replace the locomotive pickups with phosphor bronz wipers that rub on the back side of the drivers.  For now the J is banished to the roundhouse.  

The J also has issues with tractive effort -  I'll add some weight to the boiler as it struggles with 7 plastic Weaver B60's and GGD P70 passenger cars on a 2.2% grade.  I doubt it will be able to handle the heavier 6 car GGD Powhitan Arrow I have on order without the added weight.  I was surprised to find that the MTH J has less drawbar pull than similar weight brass 4-8-2's.  My guess is that sprung drivers do a better job in keeping full rail contact than unsprung ones, especially through super elevated curves.  There is also an audible difference in the sound when sprung steam (and diesel) locomotives pass through turnout frogs than unsprung ones - the unsprung ones have a noticeable "clunk".

I like the MTH J but it isn't an out of the box good runner I was expecting.

Ed Rappe

I bet it is more a function of the driver tire texture.  Plated metal has a lower coefficient of friction.  If it is stalling before the drivers slip, it is simply overweight or underpowered.

I have personally found no difference in tractive effort between sprung and unsprung steamers - when I build them I make them springable, but just put pads in the slots.  The only time I add springs is if I have a lead driver climb a rail, or if I have five or more axles.  If one driver actually leaves the rails, all that weight is transferred to the others.

I cannot hear the difference, but I have only one functioning ear, and it isn't so good.

I have an unsprung SP Atlantic - no slots either, because I was trying for dirt-simple.  Its drivers are cast iron 86", with iron (not steel) tires on the insulated side.  It is my best puller.  Strangely, I had to "spring" a Saginaw Atlantic just to make it run at all.

This H1 has blind center drivers...as does an H6 that I have.....somewhere....