trackway infrastructure guidelines for light rail ... infrastructure guidelines for light rail...

Trackway Infrastructure GuidelinesTrackway Infrastructure Guidelinesforfor

Light Rail Circulator SystemsLight Rail Circulator Systems

Presentation to:Presentation to:Presentation to:APTA Streetcar & Heritage Trolley SubcommitteeAPTA Streetcar & Heritage Trolley SubcommitteeAPTA Streetcar & Heritage Trolley Subcommitteeby: Lawrence G. Lovejoy, Parsons Brinckerhoffby: Lawrence G. Lovejoy, Parsons Brinckerhoffby: Lawrence G. Lovejoy, Parsons Brinckerhoff

December 6 2008December 6 2008December 6 2008

Trackway Infrastructure GuidelinesTrackway Infrastructure Guidelinesforfor


Authored by:Authored by:•• Russ Jackson, STVRuss Jackson, STV•• Jim Graebner,Jim Graebner,

TranSystemsTranSystems•• Larry Lovejoy, PBLarry Lovejoy, PBTechnical assistance &Technical assistance &

reviewreview•• Jack Boorse, PBJack Boorse, PB

Light Rail Circulator SystemsLight Rail Circulator Systems••Typically provide transit service within a singleTypically provide transit service within a singlemunicipal jurisdictionmunicipal jurisdiction

••Typically donTypically don’’t require speed, capacity andt require speed, capacity andmultiplemultiple--unit capability of lineunit capability of line--haul LRThaul LRT

••Must be able to negotiate street patterns inMust be able to negotiate street patterns inthe urban center, often in mixed trafficthe urban center, often in mixed traffic

••ShouldShould ““fit infit in”” with the scale of residentialwith the scale of residentialareas contiguous to the urban centerareas contiguous to the urban center

••Often require rolling stock which can negotiateOften require rolling stock which can negotiatesmaller radius curves than customary light railsmaller radius curves than customary light railstandardsstandards


Recently constructedRecently constructedexamples:examples:

•• PortlandPortland



•• PortlandPortland

•• TampaTampa



•• PortlandPortland•• TampaTampa

•• KenoshaKenosha

Vehicle Size and Curving ConsiderationsVehicle Size and Curving Considerations

De facto US LRT Standards:De facto US LRT Standards:

••Minimum Curve Radius:Minimum Curve Radius: 82 feet / 25 m82 feet / 25 m

••Vehicle Width:Vehicle Width: 2650 mm / 8.7 feet2650 mm / 8.7 feet

••Track Gauge:Track Gauge: 5656 ½½ inches / 1435 mminches / 1435 mm

Typical European Tramway Characteristics:Typical European Tramway Characteristics:

••Minimum Curve Radius:Minimum Curve Radius: 15 to 18 m (49 to 59 ft)15 to 18 m (49 to 59 ft)

••Vehicle Width:Vehicle Width: 2200 mm to 2650 mm2200 mm to 2650 mm( 7.2 to 8.7 feet)( 7.2 to 8.7 feet)

••Track Gauge:Track Gauge: 1000 to 1435 mm1000 to 1435 mm

Trackway ConsiderationsGUIDELINE #4:GUIDELINE #4:

In optimizing the trackway/vehiclerelationship ensure that the chosen vehiclecurving capabilities do not excessivelyconstrain site selection for the maintenancefacilities and storage yards. Evaluate thetrade-offs of a reduced number of vehiclesuppliers and possibly higher vehicle pricesversus greater costs for the fixed facilitiesif the site location is constrained by thevehicle capabilities.

Track Design Considerations

GUIDELINE #5:GUIDELINE #5:

Ensure that those parties responsible forwheels and rails are working in concert toproduce optimum compatibility between thetwo subsystems. Wheel gauge, track gauge,check gauge, and all new and worndimensions should all be mutually agreed toand initial drawings documenting allparameters should be developed before anyserious design work takes place.



When choosing a track designer, it is ofgreat importance that the one chosen hasdemonstrable knowledge of streetcar trackand successful design experience. Manytrack designers have primarily a railroadbackground, which by itself is notqualification for design of Light RailCirculator System track with small radiuscurves and possibly complex and compactshop and yard layout.


Rails and WheelsRails and Wheels

They are a system – not every wheelcontour will perform satisfactorily on everyrail section.

The AAR freight wheel contour (or anywheel which resembles it) is likely not thebest choice for any LRT operation with tightcurvature in embedded track situations.

Track Design ConsiderationsWheel Tread and Flange ContoursWheel Tread and Flange Contours

Typical European TramWheel

AAR 1B Narrow FlangeWheel


Rails and WheelsRails and Wheels

The wheel / rail interface surfaces shouldbe close to identical regardless of whetherthe track is embedded in the street or openballasted track.

Achieving the above with a mixture ofdomestic tee rail and overseas girder rails isdifficult at best.

Track Design ConsiderationsAmerican Transit Engineering Assn. Girder RailsAmerican Transit Engineering Assn. Girder Rails

Not rolled since the 1950’s


Trilby Rail Trilby HatTrilby Rail Trilby Hat

Track Design ConsiderationsAmerican Railway Engineering Assn Girder RailsAmerican Railway Engineering Assn Girder Rails


Track Design ConsiderationsC E N (European Committee for Standardization) Groove RailsC E N (European Committee for Standardization) Groove Rails

59Ri2 (Ri59-13) 51Ri1 (Ri51)

Track Design ConsiderationsCEN (European Committee for Standardization) Groove RailsCEN (European Committee for Standardization) Groove Rails

55G1 (35GP) 62R1 (NP4a)

Track Design ConsiderationsCEN (European Committee for Standardization) Groove RailsCEN (European Committee for Standardization) Groove Rails

56C1 (1c) 67R1 (Ph37)


GUIDELINE #7:GUIDELINE #7: Part 1Part 1

If grooved / girder rail is used, then awheel flange profile optimized for the girderrail should be adopted.

Both the gauge and guard side flange anglesfrom vertical and the tip radii on both therunning rail and guard side of the flangeshould be analyzed for use on curve radiibelow 15 meters (49 feet) and adjusted forperfect compatibility if found necessary.



Alternatively, consider adopting wheel flangeprofile and matching rail section standardsalready in successful use on a Europeanproperty which has similar curve radii tothose to be used on the Circulator System.

The flange should include the typical flat tipthat works best with flange-bearing frogs,crossings, and mates.



Bolted joints should be eliminated inembedded track as much as possible.

Absolutely unavoidable bolted joints shouldbe sandblasted and epoxy glued.

Under no circumstances use spring washersin embedded rail joints



To avoid potentialproblems due to gaugeinaccuracies, allspecialwork containingturnouts and small radiuscurves should bedesigned, fabricated andconstructed with apositive means ofmaintaining the gauge.

Track Design ConsiderationsGUIDELINE #9:GUIDELINE #9: Part 1Part 1



Full shop assembly including the gaugingdevices should be performed. All gaugingshould be carefully checked during shopassembly so as to detect any gauge devicedimensional errors.


.


Consider fabricating wheel-pair templateswhich will accurately simulate both new andworn wheel conditions. Supply of these canbe made a part of the track supplycontract.

Alternatively, a Circulator vehicle truck canbe pushed around through the track layoutto determine if appropriate rail/wheelinteraction is occurring, but it should berecognized that the worn wheel condition willnot be present without modification.



The templates or a vehicle truck can beused to check gauging of running and guardrail surfaces.

Regardless of the verification method used,checks must be done before placement ofembedding paving makes corrective actionsextremely difficult and costly.

Pavement Design Considerations

GUIDELINE #11GUIDELINE #11

Careful attention must be given topedestrian crosswalks. Flangeways mustcomply with ADA in any locations wherepedestrians can be expected. Crosswalksshould be excluded from areas of movingswitches and discouraged from any areas ofwide specialwork fabrications, such as frogs.

Pavement Design ConsiderationsGUIDELINE #11GUIDELINE #11



Where the Circulator track is in a sharedtraffic lane, the pavement construction mustbe sufficiently robust to withstand heavytraffic with virtually no maintenance.Contemporary manufactured architectural“pavers” are seldom up to such loadings,particularly in northern climates whereintrusion by salt brine is likely.


Storm water runoff carries along with itstreet detritus which can cause maintenanceproblems. Flangeways in embedded tracktherefore must be drained:

•Upstream of embedded special trackwork

•Upstream of transitions to open ballastedtrack.

Flangeways should also be drained at the lowpoint of vertical curves.



In a mixed traffic environment, anyIn a mixed traffic environment, anyvisually obvious joint in the pavement thatvisually obvious joint in the pavement thatis parallel to the rail should ideally beis parallel to the rail should ideally beoutboard of the Circulator vehicle dynamicoutboard of the Circulator vehicle dynamicenvelope, particularly if the adjoining laneenvelope, particularly if the adjoining laneis used for parking. Often, this joint willis used for parking. Often, this joint willcoincide with the maintenancecoincide with the maintenanceresponsibility limit.responsibility limit.



Coordinate with roadway pavement design toCoordinate with roadway pavement design tominimizeminimize cross slope in the track.cross slope in the track.

It isIt is notnot essential to eliminate cross slope.essential to eliminate cross slope.

Negative superelevation is acceptableNegative superelevation is acceptableprovided that speeds are limited to controlprovided that speeds are limited to controlthe overall unbalance to acceptable levels.the overall unbalance to acceptable levels.

Track Geometry Considerations


Spirals:Spirals:

••To enhance ride comfort, include eitherTo enhance ride comfort, include eitherspirals or compound transition curves at thespirals or compound transition curves at theends of any curves regardless of whether orends of any curves regardless of whether ornot the track is superelevated.not the track is superelevated.

••Spirals can also mitigate clearance issuesSpirals can also mitigate clearance issueswith circulatorwith circulator ““end overhangend overhang”” when enteringwhen enteringand leaving sharp curves.and leaving sharp curves.

Track Geometry ConsiderationsGUIDELINE #18GUIDELINE #18

Spirals can alsoSpirals can alsomitigate clearancemitigate clearanceissues withissues withcirculatorcirculator ““endendoverhangoverhang”” whenwhenentering and leavingentering and leavingsharp curves.sharp curves.

Track Geometry Considerations

Clearance Spirals



Grass Track:Grass Track:

••Consider long term maintenance issues.Consider long term maintenance issues.

••Consider snow removal in northern climates.Consider snow removal in northern climates.

••Accept that the trackway will inviteAccept that the trackway will invitepedestrian trespass and incorporatepedestrian trespass and incorporatemitigation measures in the operating plan.mitigation measures in the operating plan.

End of the line…

For questions concerning this presentation or for furtherinformation / assistance contact:

Lawrence G. Lovejoy, P.E.

Senior Supervising Engineer / Professional Associate

Parsons BrinckerhoffFour Gateway Center, Suite 1305

Pittsburgh, PA 15222-1220USA

Direct line: 1-412-644-3050Cel phone: 1-412-580-1414

e-mail: [email protected]

http://www.pbworld.com/

trackway infrastructure guidelines for light rail ... infrastructure guidelines for light rail...

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