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S-4.2 Wheels, Standard Scale

S-4.2 Wheels, Standard Scale

S-4.2

 
 

s-4.1

  K B N D
Name of Scale Check Gage
Max.		 Back-to-Back Of Flanges
Min.		 Tire Width
Min.		 Flange Depth
Max.

 

 

 

 

 
1" 4.581 4.438 .500 .156
116.4 mm 112.7 mm 12.7 mm 3.96 mm

 

 

 

 

 
  3/4" 3.349 3.219 .406 .125
85.1 mm 81.8 mm 10.3 mm 3.18 mm

 

 

 

 

 
F Except as noted, F uses the same wheel geometry as Proto 20.3 Gauge wheels
(see S-4.1)		 .090
2.18 mm

 

 

 

 

 
Fn3 Except as noted, Fn3 uses the same wheel geometry as No.1 Gauge wheels (see Note 2)
.235		 . 090
1.614
5.97 mm (2.29 mm)

 

 

 

 

 
# I 1.660 1.567 .235 .064
42.16 mm 39.80 mm 5.97 mm 1.63 mm

 

 

 

 

 
#In3 1.058 1.000 .172 .047
26.9 mm 25.4 mm 4.37 mm 1.19 mm

 

 

 

 

 
O 1.179 1.118 .172 .047
29.9 mm 28.4 mm 4.37 mm 1.19 mm

 

 

 

 

 
On3 .705 .666 .115 .030
17.9 mm 16.9 mm 2.92 mm 0.76 mm

 

 

 

 

 
On30 On30 uses the same wheel geometry as HO Gauge wheels  
 

 

 

 

 

 
On2 .455 .416 .108 .028
11.6 mm 10.6 mm 2.74 mm 0.71 mm

 

 

 

 

 
S .839 .800 .108 .030
21.31 mm 20.32 mm 2.74 mm 0.76 mm

 

 

 

 

 
Sn3 .519 .480 .108 .030
13.18 mm 12.19 mm 2.74 mm 0.76 mm

 

  K B N D
Name of Scale Check Gage
Max.		 Back-to-Back Of Flanges
Min.		 Tire Width
Min.		 Flange Depth
Max.

 

 

 

 

 
OO .705 .666 .108 .028
17.9 mm 16.9 mm 2.74 mm 0.71 mm

 

 

 

 

 
HO .605 .566 (see Note 3)
.108		 .028
15.4 mm 14.4 mm 2.74 mm 0.71 mm

 

 

 

 

 
HOn2 .246 .220 .071 .022
6.25 mm 5.59 mm 1.80 mm 0.56 mm

 

 

 

 

 
TT .437 .407 .077 .026
11.1 mm 10.3 mm 1.96 mm 0.66 mm

 

 

 

 

 
N .323 .297 .071 .022
8.20 mm 7.54 mm 1.80 mm 0.56 mm

 

 

 

 

 
Nn3 .228 .208 .053 .020
5.78 mm 5.28 mm 1.35 mm 0.51 mm

 

 

 

 

 
Nn2 .149 .131 .059 .020
3.78 mm 3.33 mm 1.50 mm 0.51 mm

 

 

 

 

 
Z .236 .218 .053 .020
5.99 mm 5.54 mm 1.35 mm 0.51 mm

NOTES:

  1. For information on both minimum and maximum manufacturing limits please see
    NMRA Tech Note: TN-1.2.1
  2. Fn3 was designed to work on #I scale track so the same track and wheel geometry was used. This results in a minimum tire width that is much narrower than the prototype. Models designed to work in dual gauge trackage with F scale need to use the F scale tire width of .271 in order for the wheels to properly navigate the frogs in the turnouts.
  3. Note: HO fine wheels will work on HO standard track but HO standard wheels will not work on HO fine track.
  4. See RP-25 for recommended Wheel Contour. Deeper Flanges conforming to STANDARD S4.3 are permitted for existing wheels when used with Track STANDARD S3.3, but wheels manufactured for this STANDARD S4.2 should not exceed the limits as shown above.
  5. Wheels shall have a scale reduction in tread diameter from the prototype.
  6. To avoid difficulty with long wheelbase locomotives in curves sharper than 20 degrees, and where guard rails are used on both sides as in special trackwork, the following are suggested: See RP-8
  • Allow lateral movement in driver axles of 1 percent of the rigid wheelbase length.
  • Remove flanges from center drivers.