Various 7 ¼” Gauge
“Standards”
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Nominal Track Gauge 7 1/4" |
Tolerances |
SMEE |
Baker |
Baker (N) |
Derby |
Evans |
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Given dimensions for track |
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Track Gauge * |
minimum |
7.250 |
7.25 |
7.25 |
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7.250 |
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Track Gauge * |
maximum |
n/s |
7.38 |
7.38 |
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n/s |
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Track back to back * |
maximum |
6.710 |
6.70 |
6.70 |
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6.710 |
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Rail head radius |
n/c |
n/s |
0.10 |
0.10 |
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n/s |
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Rail Head Width (Nominal) |
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0.50 |
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Given dimensions for wheel sets |
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Check Gauge |
+/- 0.015" |
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6.95 |
6.95 |
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Root radius |
n/c |
0.100 |
0.12 |
0.12 |
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0.100 |
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Flange thickness |
n/c |
0.154 |
0.14 |
0.19 |
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0.154 |
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Flange tip radius *** |
n/c |
0.065 |
0.06 |
0.08 |
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0.065 |
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Wheel ( tyre ) width * |
minimum |
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0.80 |
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n/c |
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1.12 |
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Wheel edge chamfer height |
n/c |
0.040 |
0.04 |
0.06 |
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0.040 |
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Chamfer angle ( degrees ) |
n/c |
45 |
45 |
45 |
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45 |
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Flange angle ( degrees ) ** |
n/c |
20 |
20 |
20 |
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20 |
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Coning angle ( degrees ) ** |
n/c |
2 |
3 |
3 |
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2 |
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Computed dimensions for wheel sets |
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Diameter Point Width |
n/c |
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0.25 |
0.30 |
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Wheel set Gauge |
n/c |
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7.08 |
7.11 |
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Wheel set back to back * |
n/c |
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6.80 |
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minimum |
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6.75 |
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Flange depth |
n/c |
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0.18 |
0.25 |
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Flange tip thickness |
n/c |
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0.10 |
0.13 |
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Track Dimensions Turnouts |
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Track Gauge |
+ 0.003 - 0 |
7.250 |
7.250 |
7.250 |
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7.250 |
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Maximum over gauge |
n/c |
n/s |
0.130 |
0.130 |
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n/s |
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Flange way |
+ 0.003 - 0 |
0.270 |
0.275 |
0.275 |
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0.270 |
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Flange lead |
n/c |
n/s |
0.193 |
0.193 |
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n/s |
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Wheel width |
n/c |
n/s |
0.525 |
0.525 |
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n/s |
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Flange depth |
n/c |
n/s |
0.372 |
0.372 |
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n/s |
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