Rail Profile - Conical or Cylindrical Wheels

Conical or Cylindrical Wheels

It has long been recognised that conical wheels and rails that are sloped by the same amount follow curves better than cylindrical wheels and vertical rails. A few railways such as Queensland Railways have always had cylindrical wheels until much heavier traffic required a change. Cylindrical wheel treads have to "skid" on track curves so increase both drag and rail and wheel wear. On very straight track a cylindrical wheel tread rolls more freely and does not "hunt." The gauge is narrowed slightly and the flange fillets keep the flanges from rubbing the rails. United States practice is a 1 in 20 cone when new. As the tread wears it approaches an unevenly cylindrical tread, at which time the wheel is trued on a wheel lathe or replaced.