Track / Rail Adhesion ValueThe worst case adhesion has long been a debatable issue. Friction measurements can easily be taken, and vary widely depending upon the conditions. (moisture, temperature, time of day, dirt/contaminant levels, etc.) As far as I know, there are no industry standards that define friction coefficients for rail systems. The table I usually reference is from a recognized tribology book, and the values are relatively typical in multiple other resources discussing steel-wheel on rail friction. The table below has typical values for wheel-rail adhesions coefficients |
| Rail Condition | Adhesions Coefficient | |
|---|---|---|
| Dry, Clean | 0.25 - 0.30 | |
| Dry, Sanded | 0.25 - 0.33 | |
| Wet, Clean | 0.18 - 0.20 | |
| Wet, Sanded | 0.22 - 0.25 | |
| Greasy | 0.15 - 0.18 | |
| Moisture, Dampness | 0.09 - 0.15 | |
| Light Snow | 0.10 | |
| Light Snow, Sanded | 0.15 | |
| Wet, with Leaves | 0.07 |
| Title hour. | 49 CFR § 238.201 |
| Title mph. | 49 CFR § 238.401 |