33" vs. 36" Wheels

[BCR751]

What is the criteria for determining whether a car needs 33" or 36" wheels?

Doug

[Kisatchie]

The weight of the car when loaded. 40' cars aren't big enough to hold enough freight to need 36" wheels, so they all use 33" wheels. Once the loads get up to 90 tons or so, then 36" wheels are usually appropriate.


Hmm... I know some people
who need 36" wheels...

[Missaberoad]

Kis is right, The short answer is the loaded capacity of the car.

typically anything 220, 000 lbs or below gets 33" wheels anything over gets 36" with a few extra heavy cars getting 38" (some modern coil cars and I'm sure others)

to calculate this add the LDLMT and LTWT on the side of a freight car

http://www.railcarphotos.com/PhotoDetails.php?PhotoID=88333
for example on this car 220,800 + 65,200  = 286,000 therefore 36" Wheels

Typically a modern cars total weight will be 220, 000, 263,000, 286,000 with some exceptions (like the >125ton cars with 38" wheels)

An easy way to tell for a specific prototype is the wheel size is typically printed on the end of the car.
http://www.tsb.gc.ca/eng/rapports-reports/rail/2013/r13d0054/Images/r13d0054-photo-09.jpg
note the 36"

Now there are exceptions, but for a general rule of thumb this works for our purposes...

edit. for spelling

[nkalanaga]

40 ft boxcars are usually 50 or 70 ton cars, so 33 inch wheels, but there are 40 ft 100 ton cars of other types, so the length isn't a reliable guide.  Some modern ore cars can carry that much, and are less than 30 ft long.  As Missaberoad said, the weight is the determining factor for freight cars. 

As far as I know, all North American standard gauge passenger cars use 36 inch wheels.

[cjm413]

40 ft boxcars are usually 50 or 70 ton cars, so 33 inch wheels, but there are 40 ft 100 ton cars of other types, so the length isn't a reliable guide.  Some modern ore cars can carry that much, and are less than 30 ft long.  As Missaberoad said, the weight is the determining factor for freight cars. 

As far as I know, all North American standard gauge passenger cars use 36 inch wheels.

SP had some 40' 100T boxcars for copper loading:

http://www.railgoat.railfan.net/spcars/byclass/box/b100-32.htm

http://www.railgoat.railfan.net/spcars/byclass/box/b100-34.htm

http://www.railgoat.railfan.net/spcars/byclass/box/b100-41.htm

[chicken45]

Most passenger cars have 36" wheels, yes?
I know that some very large flat cars has 36" wheels. Like, ones that weighed 1,000,000 lbs when fully loaded.

[nkalanaga]

CJM413:  I'm not surprised.  That's why I threw the "usually" in, there seems to always be an exception.  Somewhere there's probably a 100 ton car with 33 inch wheels...

Chicken45: That flatcar probably had a lot more than eight wheels too!

[chicken45]

Chicken45: That flatcar probably had a lot more than eight wheels too!

Sixteen, actually   Oh, and they were PRR T1 tender trucks that were used.

[nkalanaga]

I think it actually has 32 wheels, which is even bigger...

[chicken45]

I think it actually has 32 wheels, which is even bigger...

Lol. Yeah. Sixteen "axels" 

[tehachapifan]

Isn't that a song?

[chicken45]

Isn't that a song?

Yes...the 1983 hit "Axel F" from the major motion picture Beverly Hills Cop.

Let's break it down...
Axel F.
F.
F=15 in hex.
2(F) = 30
PRR FD2 flat car.
FD2
2
30 + 2 = 32
32= number of wheels on the FD2
∴ Axel F was written about the FD2.
There is no flaw in this logic.
 
 
 
 
 
 
 
 
 
   

[nickelplate759]

Most passenger cars have 36" wheels, yes?
I know that some very large flat cars has 36" wheels. Like, ones that weighed 1,000,000 lbs when fully loaded.

The old RMC drawings for the C&NW's bi-level commuter cars call out 33" wheels.  I've often wondered if that was a misprint.  Does anyone know for sure?

George

[garethashenden]

The old RMC drawings for the C&NW's bi-level commuter cars call out 33" wheels.  I've often wondered if that was a misprint.  Does anyone know for sure?

George

Not necessarily. Having 33" wheels would lower the car by 1.5", that could be important with bi-levels.