Maximum Allowable Speed on Curve

It is recognized by the authorities that the maximum acceptable rate of radial acceleration for passenger comfort is 0.1g, where 'g' is 9.81 m/s/s. Jerk is limited to 0.03g/s. This paper presents an equation for calculating the maximum allowable speed. Clearly the purpose of the equation is to achieve a gain in speed with using the existing spiral at the cost of the comfort limit. It appears that there is a consensus in breaking the standard comfort limit. The value of blanket unbalance varies from operator to operator e.g. 65mm, 75mm, 100mm etc. This variation indicates that there is no consensus in an upper limit beyond standard passenger comfort limit to determine the maximum allowable speed. This is the main reason behind the variation of unbalance adopted by different railways. Other minor reasons are ability of the vehicle to negotiate unbalance, strength of track to withstand lateral load, maintenance standard of track etc. Current use of blanket unbalance superelevation for all types of curves is flawed because it leads to different values of jerk depending on design speed, radius, and incremental unbalance on top of design unbalance. Among these different values of jerk, all values may not be acceptable. The current practice of using a blanket unbalance superelevation may not generate the maximum allowable speed. Intuitively the actual and unbalance superelevation should vary together such that a higher unbalance should go with higher actual superelevation to ensure a consistent comfort. Thus the unbalance should be different for each individual curve. To overcome the weaknesses of using a blanket unbalance superelevation and to gain higher speed, a new formula is suggested.

• Corporate Authors:

  American Society of Mechanical Engineers

  22 Law Division, P.O. Box 2300
  Fairfield, NJ  United States  07007-2300
• Authors:
  • Hasan, Nazmul
• Conference:
  • ASME/ASCE/IEEE 2011 Joint Rail Conference (JRC2011)
  • Location: Pueblo CO, United States
  • Date: 2011-3-16 to 2011-3-18
• Publication Date: 2011

Language

• English

Media Info

• Media Type: Digital/other
• Features: References; Tables;
• Pagination: 9p
• Monograph Title: ASME/ASCE/IEEE 2011 Joint Rail Conference (JRC2011)

Subject/Index Terms

• TRT Terms: Automatic train control; Curved track; Jerk control; Passenger comfort; Speed control; Superelevation; Train operation
• Subject Areas: Operations and Traffic Management; Railroads; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 01356881
• Record Type: Publication
• Files: TRIS
• Created Date: Nov 16 2011 2:51PM