p-REES 1: Module 1-F Railway Alignment Design and Geometry APTA/TCRP/FTA Basis Photos © Michael Loehr 2015

APTA Mission : To strengthen and improve public transportation, APTA serves and leads its diverse membership through advocacy, innovation and information sharing. APTA and its members and staff work to ensure that public transportation is available and accessible for all Americans in communities across the country. Photo © Michael Loehr 2015

TRB / TCRP TRB Mission : The mission of the Transportation Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal TCRP Mission : The Transit Cooperative Research Program is an applied, contract research program that develops near-term, practical solutions to problems facing transit agencies.

Federal Transit Administration (FTA) President Lyndon Johnson signed the Urban Mass Transportation Act into law on July 9, 1964. The new measure provided $375 million in capital assistance over three years. It passed the House by a vote of 212- to-129 and cleared the Senate 52-41. “We are a nation of travelers. You cannot write our history without devoting many chapters to the pony express, the stagecoach, the railroad, the automobile, the airplane. . . Yet, until 1964, the Federal Government did little or nothing to help the urban commuter.” – President Lyndon B. Johnson, on Remarks at the Signing of the Urban Mass Transportation Act Mission: To ensure personal mobility and America's economic and community vitality by supporting high quality public transportation through leadership, technical assistance and financial resources.. Purview: ‘Public transportation includes buses, subways, light rail, commuter rail, monorail, passenger ferry boats, trolleys, inclined railways, and people movers. The federal government, through the FTA, provides financial assistance to develop new transit systems and improve, maintain, and operate existing systems. The FTA oversees grants to state and local transit providers…’

Federal Transit Administration (FTA) Oversight: FTA defines oversight as a continuous review and evaluation of grantee and FTA processes to ensure compliance with statutory, administrative, and regulatory requirements. The Office of Engineering, through the Regional Offices, performs oversight of grantee project management that focuses on the management of major investments (New Starts, rail modernization, etc.) in transit projects. This activity begins early in project implementation, usually at the time of preliminary engineering. PMO contractors monitor the large caseload of projects, following guidelines established by FTA. They serve to supplement the FTA technical staff to evaluate grantee project management and technical capacity and capability to successfully implement these major transit projects. They also monitor the projects to determine whether they are progressing on time, within budget, and in accord with approved grantee plans and specifications. Other activities are also involved, such as reviews of whether a given design can in fact be constructed, change order reviews, and value engineering.

TCRP 57 and TCRP 155 TCRP 155 - Track Design Handbook for Light Rail Transit 2nd Edition TCRP 155 updates TCRP 57, but refers back to the original document. Photo © Michael Loehr 2015

Tangent Element Length Length of any track element Minimum – Based on Alignment, Equipment, Operating Speed, and Truck Centers Preferred - 3 times the velocity in mph. Example Track speed 60 mph, preferred length = 3 X 60 = 180’ Note: Individual Transit Agencies will have values specific to their system Photo © Michael Loehr 2015

Curvature Transit Practice Dc = Angle sub-tended by a 100’ Arc Why Arc Definition for Curves Specified by Radius Dc = Angle sub-tended by a 100’ Arc Why Matches Highway practices Very small radii compared to railroads Figure © Michael Loehr 2015

Curvature Minimum Radius Passenger Yards Embedded Track New Mainline r = 82’ (25m) Embedded Track New Mainline r = 500’ (150m) Photo © Michael Loehr 2015

Spirals Spirals provide smooth transition from tangents to curves Sometimes used in Highway Design, but not common practice Straight Entering Curve Full Curve Figure © Michael Loehr 2015

Spirals Functions Application Reduce lateral and jerk forces Spirals provide area to runoff superelevation Application Spirals should be used on all main line track horizontal curves with radii less than 10,000 feet. Spirals can be omitted if the calculated length of spiral (Ls) is less than 0.01R Infrequently used in Yards

Spirals LRT CADD k ≅ Ls / 2 Yo ≅ p / 2 Hickerson Clothoid p k Ls Yo Figure © Michael Loehr 2015

Spirals Figure TCRP 155

Spirals Figure TCRP 155

Spirals Figure from TCRP 155

Superelevation Picture © Michael Loehr 2015

Superelevation Figure © AREMA 2015

Superelevation Measured and described in Inches Nomenclature Eq = Equilibrium Elevation Ea = Elevation Actual Eu = Elevation Underbalance Er = Elevation Body Roll Er typically included in Eu Ec = Comfort Elevation Photo © Wikipedia® 2015

Superelevation Relationships Eq = Ea + Eu + Er Ec = Eq – Er = Ea + Eu For Standard Gage Track and Equipment Eq = 4.0 V2 / R Eu = 0.82 Ea – 0.4 Ea = 2.18 (V2 / R) – 0.22 V in Miles per Hour R in Feet E in Inches Figure TCRP 155

Superelevation Ea Max Underbalance Varies by Agency Typical 6” Photo © Michael Loehr 2015

Superelevation Maximum Speed Figure © Michael Loehr 2015

Superelevation Overturning Unbalance Superelevation The formula for computing superelevation unbalance for ‘Overturning Speed Eu’ is derived from the theory of superelevation: Eu for Overturning = Be/h Eu in inches Where; B = rail bearing distance in inches e = B/2 – x (to determine overturning) h = height of center of gravity in inches

Superelevation Overturning Speed The following formula is generalized to allow its use with any track gage. V is in mph, R is in Feet, and Eu is calculated by the preceding equation.   Overturning V = 𝐸𝑎+𝐸𝑢 ∗ 𝑅 0.067799 ∗ 𝐵

Superelevation Why is Underbalance used? To balance rail wear between both rails To reduce truck hunting by having a net outward force Ride quality Photo © Wikipedia® 2015

Grades Maximum Grades Steeper grades can be surmounted if they are short Ice and Leaf oil can limit operations on grades Light Rail Passenger Maintenance equipment may limit maximum grade Can be 7% to 9% Figure © NJTransit 2015

Vertical Curves The minimum length of vertical curves can be determined as follows: Desired Minimum Length: LVC = 200A Acceptable Minimum Length: LVC = 100A where LVC = length of vertical curve in feet A = (G2 – G1) algebraic difference in gradients in percent G1 = percent grade of approaching tangent G2 = percent grade of departing tangent V = design speed in mph

Vertical Curves The minimum length of vertical curves can be determined as follows: Absolute Minimum Length:

Vertical Curve A parabola is used for the vertical curve in which the correction from the straight grade for the first station is one half the rate of change, and the others vary as the square of the distance from the point of tangency. Where points fall on full stations, it will be necessary to figure these for only one half the vertical curve, as they are the same for corresponding points each side of the vertex. Corrections are (-) when the vertical curve is concave downwards (summit), and (+) when the vertical curve is concave upwards (sag). The rate of change per station is calculated as follows: R = D/L Where: R = Rate of change per station D = Algebraic difference of the two intercepting grades L = Length of vertical curve in 100-ft. stations M = Correction from the straight grade to the vertical curve Figure © BNSF 2015

Vertical Curves Light Rail Vehicles have capabilities for vertical curves rated based on radius The equivalent radius of curvature can be calculated from the following formula:

Clearances Light Rail Clearances may be Statutory by State The track clearance envelope (TCE) is defined as the space occupied by the maximum vehicle dynamic envelope (VDE) as defined in TCRP 155 Chapter 2, Article 2.3, plus effects due to curvature and superelevation, construction and maintenance tolerances of the track structure, construction tolerances of adjacent wayside structures, and running clearances. The relationship between the vehicle and clearance envelopes can thus be expressed as follows: TCE = VDE + TT + C&S + RC where TCE = track clearance envelope VDE = vehicle dynamic envelope TT = trackwork construction and maintenance tolerances C&S = vehicle curve and superelevation effects RC = vehicle running clearance

Clearances The following items are typically included in the development of the Vehicle Dynamic Envelope: Static vehicle outline Dynamic motion (roll) of springs and suspension/bolsters of vehicle trucks Vehicle suspension side play and component wear Vehicle wheel flange and radial tread wear Maximum truck yaw (fishtailing) Maximum passenger loading Suspension system failure Wheel and track nominal gauge difference Wheel back-to-back mounting and maintenance tolerance Figure from TCRP 155

Clearances Horizontal offsets for LRV car bodies are important considerations because of the smaller radii. Figure from TCRP 155

Michael Loehr Practice Leader Rail & Transit – Americas - Civil Transportation Business Group CH2M HILL 8720 Stony Point Parkway, Suite 110 Richmond, VA 23235 Mobile 570.575.4692 Michael.Loehr@ch2m.com