Plastic wheel sets versus metal wheel sets.

[Desert Rose]

Stock Tyco car with Tyco truck and plastic wheel sets.



Stock Tyco car with Tyco truck and metal wheel sets.



Nine feet of track with one end elevated 2 inches. Cars set at top of elevation let free roll down, coast to stop.

[Yard Master]

Good demonstration- that's why all of our Silver Series rolling stock comes equipped with metal wheels!

[jward]

I have found the biggest improvement in operation comes from using wheels with the NMRA RP25 profile. Most of the older train set cars have wheelsets that do not conform to this profile. All of the currently available metal wheelsets do. While I am sold on the metal wheelsets for other reasons (they run cleaner), even plastic wheels with the RP25 contour greatly reduce derailments. After body mounting couplers, the RP25 wheels are the biggest improvement you can make.


Yardmaster, I am impressed with the silver series cars. In addition to having metal RP25 wheels, they are also properly weighted and have body mounted couplers. They meet the standards right out of the box that I try to upgrade my older cars to. I only wish we would have had these 40 years ago.......

[Len]

Whatever type of wheels, cleaning out the journals on those older "Tyco Style" cars with a truck tuning tool will improve rolling performance even more.


Len

[trainman203]

Not discussed is the propensity of plastic wheels to spread dirt and oxidation on the rail and impede operation.  Metal wheels are much less prone to do this.

Also, I've heard some modelers state a preference for plastic wheels because unrealistic excessive tire width is not as visible when the wheels are black plastic.

H

[VTBob]

I run the cars I have that come with metal wheels, but for the most part, I stick with the usual Athearn or Accurail plastic wheels. In the space I'm in for a layout, I find it irritating when the metal wheels drown out the sound equipped locomotive, & sound like Lionel tinplate at speed. I do switch the plastic for metal in the IHC passenger cars, simply because I've found they track better on code 83 rail.

It's also just not cost effective for me to switch my entire fleet of plastic for metal, same goes for putting decoders in all of my locomotives.

Just my 2 cents,
Rob

[Ralph S]

I understand the dilemma between plastic and metal wheels, but what I don't quite understand is the differences in wheel size. 

There are 28 inch wheels in plastic or metal
There are 33 inch wheels in plastic or metal
There are 36 inch wheels in plastic or metal
There are 40 inch wheels in plastic or metal
and even seen 42 inch wheels.

Do these different sizes make the cars roll faster, like a kids bicycle over an adult bicycle?
Does it make the cars taller or shorter, causing a coupler height issue?
Not to mention whether the actual axle is plastic or metal, which also causes me to question which one of those axles are better or worse.
And lastly, will I need to purchase a caliper to measure the different wheel sizes?
I've also damaged wheel trucks cleaning out the journals, maybe cause I'm terrible at it, but making the journal larger makes the wheels wobble, in my opinion.


Anyway, I have over the many years collected both sets of wheels metal and plastic, large and small wheel diameters, and in the past just replaced wheels haphazardly to keep the train rolling.

If anyone can elaborate on this, it will be greatly appreciated.

[Terry Toenges]

Different size wheels will make the car shorter or taller. Smaller wheels would make it shorter and therefore less wind resistance so it probably would be a millisecond faster if you were just free rolling them. When your loco is pulling them they all go at the same speed.
Metal wheel and axles add extra weight on the bottom end. That is good if you have light cars.

[Len]

Not absolute, but in general the various wheel sizes show up as:

28 inch wheels will be found on cars used for double stacked containers to keep the overall height down. They are also used on some other large modern cars for the same reason.
33 inch wheels are usually found on freight cars.
36 inch wheels are usually found on passenger cars.
40 & 42 inch wheels are generally found on diesel and/or electric locomotives.

An 'outlier' in this are IHC/Rivarossi passenger cars, which come with 31 inch plastic wheels installed. There are after market sources for 31 inch metal wheels to replace them with. Or you can carve the brake shoes off the trucks and install 36 inch wheels.

Len

[Ralph S]

Darn!
 I just bought 100 of the 36-inch wheels thinking that was the size for freight cars.

[Len]

Darn!
 I just bought 100 of the 36-inch wheels thinking that was the size for freight cars.

Just think of it as a reason to start building a passenger fleet.

Len

[emde5]

Most modern freight cars, except well cars, have 36 inch wheel.

[trainman203]

I might guess that larger wheels rotate fewer revolutions per mile, eventually presenting some savings on bearing wear.  Freight trains are much faster today than they were in the days of 33 inch diameter truck wheels and friction bearings.

[trainman203]

Cars that are too-free rolling can be a problem on layouts that go beyond continuous running and become involved with switching. If the siding where setouts occur is not dead level, the car will unwantedly roll. Great care in construction is needed to prevent this. However, I live in an area with terrible soil subsidence. The house is always settling randomly and my once-level lay out now has dips here and there.

This can be a problem on the prototype as well. Devices called "derails" are installed at such locations that flip up over the top of the rail to stop errant cars from rolling out onto the main and fouling it.  Model derails are available, and I have several that I unfortunately have never gotten around to installing in the problem locations.

Long ago I heard a tip to slow these too-freerolling model cars down. To do that, you cut a Kadee coupler knuckle spring in half and put it in the journal of one side of the wheelset. For someone like me that doesn't run very long trains, it's a good idea. However, it is one that I have not gotten around to yet.

[jward]

I understand the dilemma between plastic and metal wheels, but what I don't quite understand is the differences in wheel size. 

There are 28 inch wheels in plastic or metal
There are 33 inch wheels in plastic or metal
There are 36 inch wheels in plastic or metal
There are 40 inch wheels in plastic or metal
and even seen 42 inch wheels.

Do these different sizes make the cars roll faster, like a kids bicycle over an adult bicycle?
Does it make the cars taller or shorter, causing a coupler height issue?
Not to mention whether the actual axle is plastic or metal, which also causes me to question which one of those axles are better or worse.
And lastly, will I need to purchase a caliper to measure the different wheel sizes?
I've also damaged wheel trucks cleaning out the journals, maybe cause I'm terrible at it, but making the journal larger makes the wheels wobble, in my opinion.


Anyway, I have over the many years collected both sets of wheels metal and plastic, large and small wheel diameters, and in the past just replaced wheels haphazardly to keep the train rolling.

If anyone can elaborate on this, it will be greatly appreciated.

It is my understanding that wheel size is related to the loaded weight limit of the car. The larger the wheel the more weight it is able to bear. 28 inch wheels were often found on cars like autoracks where total loaded weight wasn't much, and 36" wheels can be found on cars that when loaded reach the current 288k lb weight limit.

It is also a good general rule that freight cars of 70 ton capacity or less used 33" wheels, while those 100 tons and above used 36"

As was mentioned, 40 and 42 inch wheels are used on locomotives. A modern 6 axle locomotive like a SD70ACe can weigh up to 432k lbs, That equals the same 72k lbs per axle of the freight cars.