CE 515 Railroad Engineering - Center for Transportation

```CE 515 Railroad Engineering
Turnouts, Yard Design, &
Clearances
Arema Ch. 6
“Transportation exists to conquer space and time -”
Turnouts
• Turns one track into two
• Three basic components
Switch
Closure Curve
Frog
• Are designated by their frog number
Turnout Design
PI Method
Equivalent Curve Method
• Requivalent= 2(Gage)(Frog Number)2
• Rounded to the nearest 15
• Turnout is place with its beginning/end at the
PC/PT of the Equivalent Curve
Turnout Construction
• Provide the PS and PF for construction
• One of three methods
– Built in place
– Panelization
– Hybridization
http://www.oerm.org/pages/Turnout_construction_5_27_07_sm.JPG
Turnout Speed
• Determined by points and closure curve
• For curved points, must also consider the point of
• Self –guarded frogs are usually 15mph limit
Arema p. 249
What Does Underbalance Mean?
Underbalance is a measure of an adequate
level of superelevation for optimal
conditions. Because passenger and
freight trains have different optimal
levels, less than optimal levels are
permitted by regulatory agencies, which
limits passenger trains from traveling
their maximum speed.
https://www.nysdot.gov/regional-offices/region1/project-repository/i87MultiModalStudy/documents/draftfinal-highspeedrailsummary-may04.pdf
Frog Number
• Generally available from No. 6-24+
• Frog angle decreases as turnout number
increases
• Turnout minimum on most
mainline tracks are No. 10
Arema p. 250
Turnout Location
• Tandem Leads have a second
Turnout immediately after the
first
Arema p. 252
• Multiple turnouts in a series are called a ladder
∂=Sin-1(S/L)
∂: Deflection angle
S: Yard track spacing
L: Length of turnout
Design of Yards
• Storage Yard
• Local Yards
• Flat Switching Classification Yards
Torino, Italy
http://www.airphotona.com/stockimg/images/00200.jpg
Flat Switching Classification Yards
•
•
•
•
Receiving Yard
Classification Yard (Hump, Gravity, or Flat)
Departure Yard
Rip Track
Passenger Car Storage Yard
• Should be near the terminal
Willowbrook Yard, Toronto
http://jeffwilk.com/granduncle.php?big=13
Recruiter
http://transit.toronto.on.ca/gotransit/2304.shtml
Other Design Considerations
Lockers and toilets
Equipment storage
Fueling and servicing
Minor repair facilities
Turntables
Air compressors
Floodlighting
Cleaning stations
Wastewater and oil treatment facilities
http://www.flickr.com/photos/grundlepuck/151676388/
Clearance
The space required between the track and
other fixed obstructions, including other
track
Determined by
• Type and Size of locomotive
• Type and size of cars
http://www.panoramio.com/photo/6355575
Lists and calculation procedures can be
found in Arema Chapter 28
Clearance
• Side clearance is
measured from the
center of the track
• Must be increased on
Curves
measured from the above
top running rail.
http://gritton.org/greg/rail/docs/clearance/AAR_plates_with_UIC.gif
Swingout Clearance
• Maximum swingout occurs at the mid point
of two cars
Over hang distance, s, from centerline
S=m + w/2 Where,
m=R-(2*R-(t/2)*2)1/2
t= truck centers
w=railcar width
Arema p. 259
Superelevation Clearance
e=E*t/G
Where,
E=superelevation
t= height of car
G= Gauge distance
http://zierke.com/shasta_route/picpages/rb22994.html
So e+m is the additional clearance needed