While several other tutorial topics discussed creating vertical and horizontal alignments with multiple element connection and regression analysis, this chapter details how to create a cant alignment from an existing horizontal alignment. In rail design, the cant (angular tilt of the track) alignment is
necessary to counteract the centrifugal forces imposed in a horizontal curve.
Cant is analogous to superelevation (common in roadway design) and the terms are frequently used interchangeably.
While a single (parent) horizontal alignment is required, it may actually have several cant alignments associated with it.
These various cant alignments allow you to create several different design alternatives for a rail project.
Typically, a geometry project is established, including creating or loading a horizontal alignment. Cant alignments can then be created based on the existing horizontal elements. In Bentley Rail Track, a cant alignment is created in two ways: 1) values are computed by an equation using various design parameters that you provide or 2) cant values for each station are selected from an ASCII file lookup table, which contains
us and cant values. Once cant values are available, the Cant Alignment Editor command allows you to add to or modify these values.
In this task, you will create a cant alignment for a single track.
Once you have created and modified an alignment, you ca model the rail design using the Roadway Designer command (detailed in the chapter, Running Roadway Designer in Railway Design).
Before Getting Started
While several other tutorial topics discussed creating vertical and horizontal alignments with multiple element connection
lysis, this chapter details how to create a cant alignment from an existing horizontal alignment. In rail design, the cant (angular tilt of the track) alignment is
necessary to counteract the centrifugal forces imposed in a gous to superelevation (common in roadway design) and the terms are frequently used interchangeably.
While a single (parent) horizontal alignment is required, it may actually have several cant alignments associated with it.
allow you to create several Typically, a geometry project is established, including creating or loading a horizontal alignment. Cant alignments can then
ts. In Bentley Rail Track, a cant alignment is created in two ways: 1) values are computed by an equation using various design parameters that you provide or 2) cant values for each station are selected from an ASCII file lookup table, which contains
us and cant values. Once cant values are available, the Cant Alignment Editor command allows you to add to or
In this task, you will create a cant alignment for a single track.
Once you have created and modified an alignment, you can model the rail design using the Roadway Designer command
Running Roadway Designer in
Locate the tutorial data in Files\
Loading
17. Go to Start>Programs>Bentley>InRoads Group XM and load the product “Bentley Rail Track”.
18. From
rail_tutorial.dgn 19. Click File > Open.
20. Set the directory to Files
21. Select 22. Select 23. Select
24. Click Cancel to dismiss the dialog box.
Creating a Cant Alignment Slot To begin
Alignment information resides in memory until the geometry project
1. Click File > New.
2. Click the Geometry tab.
3. For Type, select Cant.
4. For the Name, type 5. Click Apply; then Close.
Creating a cant alignment first involves setting global parameters that will affect all of the initial cant station values. For this task, the parameters have already been selected. Next, you will take a look at these defau
settings prior to creating the cant alignment.
Reviewing Global Cant Settings Locate the tutorial data in C:\Program
\Bentley\Tutorials\Rail. Extract RailChaper14.exe Loading Your Files
Go to Start>Programs>Bentley>InRoads Group XM and load the product “Bentley Rail Track”.
From C:\Program Files\Bentley\Tutorials\Rail rail_tutorial.dgn or rail_tutorial.dwg file.
Click File > Open.
Set the directory to C:\Program Files\Bentley\Tutorials\Rail.
Select railm_tut.xin, and click Open.
Select existing.dtm, and click Open.
Select singletrack.alg, and click Open.
Click Cancel to dismiss the dialog box.
Creating a Cant Alignment Slot
To begin, create a slot in memory to store the cant alignment.
Alignment information resides in memory until the geometry project (*.alg) is saved again.
Click File > New.
Click the Geometry tab.
For Type, select Cant.
For the Name, type cant. Press the TAB key.
Click Apply; then Close.
Creating a cant alignment first involves setting global parameters that will affect all of the initial cant station values. For this task, the parameters have already been selected. Next, you will take a look at these defau
settings prior to creating the cant alignment.
Reviewing Global Cant Settings
RailChaper14.exe.
Go to Start>Programs>Bentley>InRoads Group XM and Rail open the
, create a slot in memory to store the cant alignment.
Alignment information resides in memory until the geometry
Creating a cant alignment first involves setting global parameters that will affect all of the initial cant station values. For this task, the parameters have already been selected. Next, you will take a look at these default global
In Bentley Rail Track, default cant settings are located on the Rail tab in the Options dialog box. Later, when you define the cant stations and compute cant values, the settings located here will apply; however, they can be modified at any time using the Cant Editor command. You will modify cant values later in the workflow
1. Click Tools > Options.
2. Click the Rail tab.
3. For Design Speed, type 100. Press the TAB key.
4. Click Apply.
5. Review the remaining settings:
• Design speed specifies speed for the alignment.
• Equilibrium Constant specifies the constant value used to compute equilibrium cant. Equilibrium cant is the theoretical amount of cross-sectional inclination
necessary to negate the centrifugal forces imposed by a horizontal curve.
• Applied Constant specifies the constant value used to compute applied cant. Applied cant is the actual cant applied to a portion of track.
• Cant Rounding Constant is the value, in millimeters or inches, used to mathematically round a computed applied cant to the specified interval.
•
6. Click Close to dismiss the dialog box.
Defining the Cant Alignment
A cant alignment consists of a list of cant values. These values are computed based on the given horizontal alignment, design speed, equilibrium constant, applied constant, and the track gauge. These values
station, and each station contains defining information about the cant at that location. Cant stations may correspond to the cardinal points in the (parent) horizontal alignment.
Cant values are computed using the C
You can also use this command to modify, delete, or report on an entire cant or only a portion of the alignment.
Using the Cant Editor
Previously, you opened a horizonta
slot in memory for the new cant alignment. Next, compute a cant alignment.
1. Click Geometry > Superelevation > Cant Editor.
• Centerline Rail to Centerline Rail and Inside Rail to Inside Rail Distance are two different methods for specifying gauge.
• Virtual Transition Length is the length to which cant is applied when a transition spiral is not required.
• Percent Linear is the amount of cant transition applied on a linear element of an alignment that does not contain spirals.
• Rotate Cant About specifies the point around which the cant is rotated. These options allow rotating about the:
Inside Rail, Center, Outside Rail, Left Rail, or Right Rail.
• Add Cant at Spiral to Spiral Station provides instruction for a reverse spiral situation. When
checked, this option instructs the software to include a cant point at the spiral-to-spiral transition.
• Compute Turnouts based on Mainline Cant instructs the software to create turnouts by adjusting the ratio at .0 so that the resultant angle is measured in a plane defined by the cant of the mainline alignment.
Click Close to dismiss the dialog box.
Defining the Cant Alignment
A cant alignment consists of a list of cant values. These values are computed based on the given horizontal alignment, design speed, equilibrium constant, applied constant, and the track gauge. These values are stored in a list that is ordered by station, and each station contains defining information about the cant at that location. Cant stations may correspond to the cardinal points in the (parent) horizontal alignment.
Cant values are computed using the Cant Alignment Editor.
You can also use this command to modify, delete, or report on an entire cant or only a portion of the alignment.
Using the Cant Editor
Previously, you opened a horizontal alignment and created a slot in memory for the new cant alignment. Next, compute a cant alignment.
Click Geometry > Superelevation > Cant Editor.
Centerline Rail to Centerline Rail and Inside Rail to Inside Rail Distance are two different methods for Virtual Transition Length is the length to which cant is applied when a transition spiral is not required.
s the amount of cant transition applied on a linear element of an alignment that does not Rotate Cant About specifies the point around which the cant is rotated. These options allow rotating about the:
eft Rail, or Right Add Cant at Spiral to Spiral Station provides
instruction for a reverse spiral situation. When
checked, this option instructs the software to include a line Cant instructs the software to create turnouts by adjusting the ratio at .0 so that the resultant angle is measured in a plane defined by the cant of the mainline alignment.
A cant alignment consists of a list of cant values. These values are computed based on the given horizontal alignment, design speed, equilibrium constant, applied constant, and the track
are stored in a list that is ordered by station, and each station contains defining information about the cant at that location. Cant stations may correspond to the cardinal points in the (parent) horizontal alignment.
ant Alignment Editor.
You can also use this command to modify, delete, or report on
l alignment and created a slot in memory for the new cant alignment. Next, compute a
Click Geometry > Superelevation > Cant Editor.
2. Click Define All.
These values have been previously defined on the Tools >
Option > Rail tab.
3. Click OK.
The Define All option allows you to compute cant values for all elements of the alignment at one time.
4. Click Apply.
The alignment is computed based on the Rail settings and/or the values in the Define Cant Alignment dialog box.
These values are list
begins with a Point of Beginning (POB) element, leading with a Tangent into a Spiral followed by a series of Spirals Click Define All.
These values have been previously defined on the Tools >
Option > Rail tab.
Click OK.
The Define All option allows you to compute cant values for all elements of the alignment at one time.
Click Apply.
The alignment is computed based on the Rail settings and/or the values in the Define Cant Alignment dialog box.
These values are listed in order of station. The sequence begins with a Point of Beginning (POB) element, leading with a Tangent into a Spiral followed by a series of Spirals These values have been previously defined on the Tools >
The Define All option allows you to compute cant values for
The alignment is computed based on the Rail settings and/or the values in the Define Cant Alignment dialog box.
ed in order of station. The sequence begins with a Point of Beginning (POB) element, leading with a Tangent into a Spiral followed by a series of Spirals
and Curves. The element terminates at the Point of Ending (POE).
Next, you will add a station entry speed.
5. Click on the last SC in the list.
6. Click Add.
7. For Station, type 8. For Design Speed, type 9. Click Apply; then, Cancel.
Next, edit the design speed for the last three cant elements. You could select each element in
modify the value (as you did in step 5), or you can modify several elements at one time.
10. Multi
and Curves. The element terminates at the Point of Ending (POE).
Next, you will add a station entry and slow the design speed.
Click on the last SC in the list.
Click Add.
For Station, type 2+300.00.
For Design Speed, type 80.00.
Click Apply; then, Cancel.
Next, edit the design speed for the last three cant
elements. You could select each element individually and modify the value (as you did in step 5), or you can modify several elements at one time.
Multi-select the last three cant elements.
and Curves. The element terminates at the Point of and slow the design
Next, edit the design speed for the last three cant
dividually and modify the value (as you did in step 5), or you can modify
11. Click Edit.
12. For Design Speed, type
13. Click OK.
14. Click Apply to store the 15. Click Report.
Click Edit.
For Design Speed, type 80.00. Press the TAB key.
Click OK.
Click Apply to store the additions and changes.
Click Report.
. Press the TAB key.
16. Click Save As to save the alignment report; then, click Print (optional).
17. Close the Results dialog box.
18. Cancel the Cant Alignment Editor dialog box.
You have successfully created a cant alignment, modified cant elem
Although you don’t see any changes to the design file here, you can view these changes when you run the Modeler command
19. Click File > Save > Geometry Project.
20. Using your CAD software, save the rail_tutorial.dwg
21. Click File > Exit and exit your CAD software or continue to Chapter 15,
Click Save As to save the alignment report; then, click Print (optional).
Close the Results dialog box.
Cancel the Cant Alignment Editor dialog box.
You have successfully created a cant alignment, modified cant elements, and generated an alignment report.
Although you don’t see any changes to the design file here, you can view these changes when you run the Modeler command
Click File > Save > Geometry Project.
Using your CAD software, save the rail_tutorial.dgn rail_tutorial.dwg file.
Click File > Exit and exit your CAD software or continue to Chapter 15, Creating Turnouts.
Click Save As to save the alignment report; then, click Print
You have successfully created a cant alignment, modified ents, and generated an alignment report.
Although you don’t see any changes to the design file here, you can view these changes when you run the Modeler
rail_tutorial.dgn or Click File > Exit and exit your CAD software or continue to
14
Overview
Several Bentley Rail Track tutorial discussions demonstrate creating vertical, horizontal and cant alignments. In this chapter, however, you will create turnouts. Generally, a turnout is a term for a single track that splits to become two tracks and is
These connections allow a smooth transition from the main track to the diverging track.
Turnouts may contain branches with each branch containing elements. These elements may be linear, circular, or clothoid elements. In this task, you create a simple turnout for a single track.
Before Getting Started
Locate the tutorial data in Files\
Loading Your Files
25. Go to Start>Programs>Bentley>InRoads Group load the product “Bentley Rail Track”.
26. From
rail_tutorial.dgn 27. Click File > Open.
28. Set the directory to Files
29. Select 30. Select
31. Click Cancel to dismiss the dialog box.
Creating a Parallel Track
To begin, you must create a track parallel to the existing mainline alignment.