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CE 515 Railroad Engineering
Track
Source: Armstrong Ch 3, AREMA
Ch. 3, REES Module 2
“Transportation exists to conquer space and time -”
Track Alignment
• How is Alignment Measured in Tangent
Track?
Track Alignment
• How is Alignment Measured in Curved
Track?
• Mid-Ordinate Offset (in)=Degree of
Curvature
Horizontal Curve Elements
Horizontal Curve Elements
http://zierke.com/shasta_route/picpages/atsf120williamsjct.html
Horizontal Curve Elements
http://thomascranelibrary.org/jpg/legacy/fig50.jpg
Gage
• Measuring Gage
Gage
• Max Gage allowance 1-3/4” wider
• Class 4 Operation, 1” max
http://img.photobucket.com/albums/v329/Trainman-2/SCRM%20West%20End/IMGP4575.jpg
Turnouts
• 3 Groups of Turnouts
– Lateral Turnouts
– Equilateral Turnouts
– Lap Turnouts
http://s145079212.onlinehome.us/rr/howto/faq/faq_turnouts.htm#lapturnout
Turnouts
Bingmaps.com
Turnout Terminology
• Also See AREMA pp. 89-90
Fig 3-13 from Armstrong
The Switch
• Device deflecting wheels of train from
track they are running
• Switch is portion of turnout from Point of
Switch (PS) to Heel of Switch (HS)
• Video (model):
http://www.youtube.com/watch?v=FF8YIH160hA
The Switching Mechanism
• Hand operated (switch stand)
• Power operated (machine)
Frog
• Permits flange of wheel to cross the other
rail
http://static.panoramio.com/photos/original/6940512.jpg
Frog Types
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•
•
•
•
Rail Bound Manganese (RBM)
Spring Frog
Solid Manganese Self-guarded Frog
Bolted Rigid Frogs
Movable Point Frogs
Guard Rails
Railway Crossovers and Crossings
• Crossovers can be considered as two turnouts
• Crossing consists of 4 frogs (2 intersecting
tracks)
Railway Crossovers and Crossings
• Slip Switch: combination of small angle
crossing with pair of connecting tracks within
limits of crossing
Railway Crossovers and Crossings
• Information needed to design crossings
– See AREMA pp. 105-6
• Specialty manufactures design these features
• Train Crossing Frog: http://www.youtube.com/watch?v=jeWxWkTlsUE
• How they work:
http://video.google.com/videoplay?docid=2853660703765713140&ei=xnFeS-
28K5jqqwKsyI3oCg&q=Railroad+Frog&hl=en&client=firefox-a#
Highway Crossings
• Renewal of Crossings are Expensive
• Public Safety is Serious Concern
Highway Crossings