gap between a closed point rail / switch rail / point blade and stock rail (in closed position)
Klaffmass = horizontaler Abstand zwischen Zunge und Backenschiene in geschlossenem Zustand.
Point rails, also named switch rail or point blades, which lie between the diverging stock rails, are movable and direct the trains coming from the rail points towards either the straight or the diverging track.
Analysis of derailment cause severity by the University of Illinois2 ranked derailment causing turnout component defects as follows.
- Switch point - worn or broken
- Other frog, switch and track appliance defects
- Turnout frog - worn or broken
- Switch connecting or operating rod - broken or defective
- Switch point - gap between switch point and stock rail
This is consistent with a separate Transit Cooperative Research Program (TCRP) study,3, 4 which listed the following derailment causing turnout conditions.
- Wear/failure of stock rail
- Failure of the switch mechanism
- Improper adjustment of switch
- Wear/failure of frog, wear/failure of the switch point
- Gap between switch point and stock rail
Switch width includes effects of side wear on stock rails and closed gap between switch and stock rails. It is not recommended that the gap between the switch rail and stock rail exceeds 3mm at any time.
| Jacek Kloskowski|
Local time: 04:29
Works in field
Native speaker of: Polish, English