MTH Scale Wheels vs High Wheels

Let me try to be more exact. . . if I'm running Fastrack 0-36 curves and I want to buy my first MTH train. . .let's say a 20-20225. . .there are two flavors, -1 or -2. Scale wheels or Hi Rail. Both models say they run on 0-31 curves. What's the difference? Why would I want one over the other?

Not so. The scale one operates on 31 inch radius, while the hi-rail operates on O-31 (which is diameter). So in your case with O-36 you would need the hi-rail version.

doug,

 

the mth engine with the last number -1 is for three rail. and will run on three rail track down to the curve it says on the box. most 20- premier diesels will run on a O-42 curve.

 

the mth engine with the last number -2 is for two rail. IF YOU CHANGE OUT THE scale wheels for the hi-rail wheels it will run on three rail track. BUT YOU NEED TO REMEMBER that the fixed pilot needs a O-72 curve for three rail track because you still will be using kadee couplers. 

Does the Hi Rail mean that it sits higher on the rail? Does that cause problems with coupling to rolling stock? What does one have to look for in the product description when buying rolling stock?

The term "Hi-Rail" simply means that everything associated with the layout is scale exempt for the fact that the track is 3 rail and the profile of the track is higher than it would be if it where scale, therefore the term "Hi-Rail". As far as rolling stock all hi-rail equipment should work well together, the only issues is when you start modifying stuff as mentioned above. As far as description, as long as it says 3 rail you should be ok.

You are confusing "Hi-Rail" with "height". The Hi-Rail wheel models are for operation on 3-Rail, O gauge track (AC power center rail). The 2-Rail Scale versions are for operation on 2-Rail Scale track DC power). The Hi-Rail models have the standard "lobster claw" couplers and will couple up with all you other 3-Rail pieces of rolling stock.

Whew, OK I think I get it. DL&W Pete, if the spec's say it runs on 0-31 curves, why did you say it needs a 0-72 curve?

You are confusing "O-31 curves" with "31 inch Radius" curves. For example, "O-31 curves" in the "3-Rail Trains" world is only 15 & 1/2 inch radius. 

 

In the 2-Rail Scale world, a "31 inch RADIUS" curve translates to an "O62 curve" in the  3-Rail Trains world.

 

Very confusion for a new-be, isn't it?

For reference, here is a pick of my SD70M-2 Demonstrator MTH item #20-2830-1.

It is the "Hi-Rail Wheels" version.  it has swinging pilot to operate on curves as small as 0-42.  In the photo, you'll notice the gap between the pilot and the frame.

 

 

Below, you can see how the front stairs swing apart as it rounds an 0-72 curve...the scale wheels version wouldn't...

 

doug,

 

hi-rail version the coupler and pilot will swing with the curve just like the above pictures.

 

scale wheel version the coupler is a kadee mounted to the FIXED pilot, which does not move with the curve. so with the coupler BODY mounted, you will need a larger curve for the engine and cars not to derail.

 

as hot water said above, O-31, O-36, O-42, O-45, O-48, O-54, O-63, O-72 is just that in 3 rail track.

 

do not confuse curve with radius. if it says 36 radius on the box, times that by 2.

36x2= 72 radius circle for that engine.

 

so if you buy a scale wheel engine and replace them with hi-rail wheels, you can run that engine on three rail track. but you still have the fixed pilot with a body mounted kadee coupler, you will still need to run the engine on a O-72 curve.

 

alot of people are building 3 rail scale layouts now, they want the look of two rail with the close body mounted kadee couplers and scale wheels on 3 rail track. 

This is an example of a "scale wheels" engine.

So yes or no. If the MTH specs for a high rail says it will run on 0-31 curves will it.

Sorry, I mean fastrack 0-36.

Doug,

 

Some of the answers you've received have gone way beyond what you were asking.

 

When MTH says hi-rail wheels they are talking about an engine with the same type wheels as has been traditionally used on 3 rail trains since the postwar Lionel years and beyond.

 

You want the hi-rail wheel version. It will be compatible with all your present 3-rail equipment. If the engine you are looking at says it runs on O31, then it will be fine on your Fastrack curves.

 

The scale wheel engines are for specific track systems and a different slant on modeling than you want right now.

 

Jim

To put it simply, MTH usually lists 2 minimum curves. If the number starts with an "O" like O-31, O-36, O-42, O-54, O-72, etc... That is the size of the 3 rail curve required for the "-1" version. 3 Rail track is labeled by its diameter so O-36 = 36in diameter. The other number you may see will be listed in inches such as 31"r or 40"r which is the radius (half of the diameter) of the required curve. This applies to the "-2" Scale wheel engines on 2 Rail or 3Rail track. So if you want a "-2" engine that has a 40"r requirement and you want to run it on 3 rail track you would need O-80 curves. Make sense?

 

Hope that helps.

To keep it simpler, you should get a -1.  I purchased an MTH -2 years ago and even with Atlas 0-108 the engine would not negotiate the curves.  After laying 2 rail track for part of my layout with what would be 0-144, I finally got the engine to run.  Not all -2 engines need that wide a diameter, but if you are using some Fastrack with 0-36 curves the -1 is for you. 

 

HiRail is an ancient term that refers to taking 3 rail equipment and trying to make it as scale oriented as possible.  The wheels of a high rail engine are the same diameter as a scale engine, but the flanges are larger to accommodate what is needed to operate on 3 rail track.

 

The two engines closest are HiRail (large 3 rail flanges), the engine furthest back is an MTH -2 on 2 rail track.  

 

If you click on the picture you might just be able to compare the engine (pilot) truck flanges on the engines and you will see that the flanges on the -2 are not as large.

 

 

Doug:

 

If you want to learn about the various O gauge car sizes check out this Post on another Forum.

 

http://www.modeltrainforum.com/showthread.php?t=5126

 

Hope this is legal.

 

Bud

I think originally the use of the term Hi-Rail was used to describe a highly detailed and sceniced 3-rail layout and less to do  taking 3 rail equipment and trying to make it as scale oriented as possible. However available  scale sized equipment and locomotives were generally used but not always.

Yep. What Charlie said. You can have Hi-Rail with semi-scale equipment too. Actually if you consider the Lionel display layouts and Model Builder layouts most published layouts were "Hi-Rail". But that is a topic for another thread.

Thanks to all for the comments. . .finally got it!