ADHESION AND FRICTION IN RAIL TRACTION

For dry rails, a coefficient of adhesion of 0.25 may be assumed for speeds up to 40-50 m.p.h. At higher speeds, however, there is less information to draw on. Above the 40-50 m.p.h. range, the dependence of adhesion on speed introduces a bend into the curve connecting speed and power output. For wet rails, the coefficient of adhesion is reduced to about 0.6 of the value determined for dry rails. Of the many variables encountered in brake-block friction, there is abundant evidence of the dependence of coefficient of friction on speed and brake-block pressure. Substances should be saught for blocks for which the coefficient of friction is less affected by speed than in the case of cast iron; the effect would be to allow acceptable braking distances without having to use high braking ratios, so that a reduction in the weight of brake gear could be contemplated.

• Corporate Authors:

  Temple Press Limited

  161-166 Fleet Street
  Longon EC4,   England 
• Authors:
  • Koffman, J
• Publication Date: 1948-10-29

Media Info

• Pagination: p. 484
• Serial:
  • RAILWAY GAZETTE
  • Volume: 89

Subject/Index Terms

• TRT Terms: Adhesion; Brakes; Braking; Dynamics; Friction; Railroad rails; Technology; Train track dynamics; Velocity; Wheels
• Geographic Terms: United Kingdom
• Old TRIS Terms: Braking systems
• Subject Areas: Railroads; Vehicles and Equipment;

Filing Info

• Accession Number: 00039475
• Record Type: Publication
• Files: TRIS
• Created Date: Dec 4 1994 12:00AM