Week 10: Design of the Rail Cross Section

FINAL, BUT DO NOT PRINT! I WILL BRING TO CLASS!

Text (14 pages):

Supp. Text:

Objective: To gain knowledge of cross section components, understand their relative contribution to cross section design, be able to apply the concepts by designing a functional cross section


Cross Section

Rail Guage

Superelevation

Ballast

  1. distribute loads (depth 6 - 30 inches); loads are reduced from 100 psi just under the tie to less than 50 psi at the top of the subgrade
  2. reducing the load allows the subgrade to hold up and not settle (load less than endurance limit)
  3. anchor ties ("interlocking" is required, so crushed stone is preferred to river gravel)
  4. provide drainage (use open graded materials, 1.5 inch diameter.) - problem with too many fines will be ____________________________________
  5. control weeds and dust
  1. Wear resistance
  2. Cleanliness (can be improved by use of geofabrics)
  3. Frost Resistance
  4. Unit Weight (e.g., slags)
  5. Ballast will usually last for ________ Million gross tons (25,000 trains at 10,000 tons each)
Crossties

  1. spread loads
  2. maintain guage
  3. prevent longitudinal and lateral movement
  4. deflect to cushion impact
  5. making small vertical adjustments
Rails

Frogs, switches and turnouts

Fasteners

Sketch a functional cross section, labeling all of its parts. Include plan, profile and cross-section views.

Plan:

Profile:

Cross Section: