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your portal to more fun in scale model railroading
These Clearances and Track Centers provide for Interchange and satisfactory operation of interurban and street railway equipment only.
Heavy multiple-unit cars or electric locomotives operating under standard railroad conditions, and a few exceptionally large interurban types, are subject to the requirements of STANDARDS S-7 and S-8 (Class I).
1. "Clearance" as used herein is the minimum safe allowance from the track centerline to poles, structures or other trackside objects. It consists of the actual maximum deviation of the car body from the track centerline, plus an allowance of one scale foot to provide for rocking of the car body or track irregularities.
2. "Track Center" values provide such additional allowances as are necessary to insure safe passage of cars on adjacent tracks.
3. The data herein is based on an interurban car 62' in length over anticlimbers, 55' between corner posts, 40' between truck centers, and 10' extreme width. Thus it accommodates any city and almost all American interurban types.
| Prototype Radius - Ft | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 35 | 45 | 60 | 75 | 100 | 125 | 150 | 175 | 200 | Tangent |
| 1/2" Scale | |||||||||
| Radius - inches | |||||||||
| 17-1/2 | 22-1/2 | 30 | 37-1/2 | 50 | 62-1/2 | 75 | 87-1/2 | 100 | |
| Clearance, inside | |||||||||
| 6-1/8 | 5-7/16 | 4-3/4 | 4-3/8 | 4-1/16 | 3-7/8 | 3-3/4 | 3-5/8 | 3-1/2 | 3 |
| Clearance, outside | |||||||||
| 4-3/4 | 4-9/16 | 4-5/16 | 4-1/16 | 3-7/8 | 3-3/4 | 3-5/8 | 3-1/2 | 3-3/8 | 3 |
| Track Centers | |||||||||
| 10 | 9-5/16 | 8-5/8 | 8-1/8 | 7-3/4 | 7-1/2 | 7-3/8 | 7-1/4 | 7-1/8 | 6-1/4 |
| O Scale | |||||||||
| Radius - inches | |||||||||
| 8-3/4 | 11-1/4 | 15 | 18-3/4 | 25 | 31-1/4 | 37-1/2 | 43-3/4 | 50 | |
| Clearance, inside | |||||||||
| 3-1/16 | 2-23/32 | 2-3/8 | 2-3/16 | 2-1/32 | 1-15/16 | 1-7/8 | 1-13/16 | 1-3/4 | 1-1/2 |
| Clearance, outside | |||||||||
| 2-3/8 | 2-9/32 | 2-5/32 | 2-1/32 | 1-15/16 | 1-7/8 | 1-13/16 | 1-3/4 | 1-11/16 | 1-1/2 |
| Track Centers | |||||||||
| 5 | 4-21/32 | 4-5/16 | 4-1/16 | 3-7/8 | 3-3/4 | 3-11/16 | 3-5/8 | 3-9/16 | 3-1/8 |
| S Scale | |||||||||
| Radius - inches | |||||||||
| 6-9/16 | 8-7/16 | 11-1/4 | 14-1/16 | 18-3/4 | 23-7/16 | 28-1/8 | 32-13/16 | 37-1/2 | |
| Clearance, inside | |||||||||
| 2-9/32 | 2-1/32 | 1-25-32 | 1-23-32 | 1-17/32 | 1-7/16 | 1-13/32 | 1-3/8 | 1-5/16 | 1-1/8 |
| Clearance, outside | |||||||||
| 1-25/32 | 1-11/16 | 1-5/8 | 1-17/32 | 1-7/16 | 1-13/32 | 1-3/8 | 1-5/16 | 1-9/32 | 1-1/8 |
| Track Centers | |||||||||
| 3-3/4 | 3-1/2 | 3-1/4 | 3-1/16 | 2-29/32 | 2-13/16 | 2-3/4 | 2-23-32 | 2-11/16 | 2-3/8 |
| HO Scale | |||||||||
| Radius - inches | |||||||||
| 4-13/16 | 6-3/16 | 8-9/32 | 10-11/32 | 13-25/32 | 17-7/32 | 20-21/32 | 24-1/8 | 27-9/16 | |
| Clearance, inside | |||||||||
| 1-11/16 | 1-1/2 | 1-5/16 | 1-7/32 | 1-1/8 | 1-1/16 | 1-1/32 | 1 | 31-32 | 13/16 |
| Clearance, outside | |||||||||
| 1-5/16 | 1-1/4 | 1-3/16 | 1-1/8 | 1-1/16 | 1-1/32 | 1 | 31-32 | 15/16 | 13/16 |
| Track Centers | |||||||||
| 2-3/4 | 2-9/16 | 2-3/8 | 2-1/4 | 2-1/8 | 2-1/16 | 2-1/32 | 2 | 1-31/32 | 1-3/4 |
| N Scale | |||||||||
| Radius - inches | |||||||||
| 2-5/8 | 3-3/8 | 4-1/2 | 5-5/8 | 7-1/2 | 9-3/8 | 11-1/4 | 13-1/8 | 15 | |
| Clearance, inside | |||||||||
| 29/32 | 13/16 | 23/32 | 21/32 | 39/64 | 37/64 | 9/16 | 35/64 | 17/32 | 7/16 |
| Clearance, outside | |||||||||
| 23/32 | 11/16 | 21/32 | 5/8 | 37/64 | 9/16 | 35/64 | 17/32 | 33/64 | 7/16 |
| Track Centers | |||||||||
| 1-1/2 | 1-13/32 | 1-5/16 | 1-7/32 | 1-5/32 | 1-1/8 | 1-3/32 | 1-5/64 | 1-1/16 | 15/16 |
NOTE: Track Centers are based on the centerline radius of the inner track.