Left_Hand_Multi

The Left_Hand_Multi_Track subassembly is used for a single railroad that includes sleepers, ballast, subballast, and two additional layers or materials which can be used for Sub Base and Soil Fill material.

The dimensions of the Left_Hand_Multi_Track rails can be edited as well as the dimensions of the material layers.

Note: For this subassembly, the right side elevation should be lower than the top of the ballast. If the right side elevation is higher than the top of ballast, the result will be incorrect. If you need this subassembly to behave differently, you can use the Subassembly Composer to modify the existing PKT file to suit your needs. Subassembly PKT files are located in C:\ProgramData\Autodesk\C3D <version>\enu\Subassemblies\<unit>.

Attachment

By default, the attachment point is at the centerline between the rails. The track can be moved relative to this point using the subassembly parameters.

Input Parameters

Note: All dimensions are in meters or feet unless otherwise noted. All slopes are in run-over-rise form (for example, 4 : 1) unless indicated as a percent slope with a “%” sign.

Parameter	Description	Type	Default
Measure Cant At	Determines whether the elevation difference between rails takes place between the gauge line (face) of each rail or CL of each rail.	Selection List: Gauge Line to Gauge Line CL Rail to CL Rail	CL Rail to CL Rail
Default Cant	The default elevation difference between rails. The value is positive when the right rail is higher than the left and negative when the right rail is lower than the left. This value is applied in layout mode and is helpful for observing how the subassembly reacts to different cant values. This value is overridden by cant when it is present via the baseline alignment.	Numeric	0
Drainage Channel Depth	Depth of right drainage channel from top of ballast.	Numeric, non-negative	0.5 ft 0.1524 m
Gauge	The distance between the inside faces of the rails	Numeric, non-negative	56.5" 1435 mm
Rail Head Width	Width of the rail head.	Numeric, non-negative	2.72" 69 mm
Rail Depth	Depth of rail from top of rail to top of tie plate	Numeric, non-negative	6.625" 168 mm
Rail Base Width	Width of the base of the rail	Numeric, non-negative	5.5" 140 mm
Tie Plate Thickness	Thickness of the tie plate which is also the distance from the bottom of the rail to the top of the tie.	Numeric, non-negative	1" 25 mm
Rail Base to Ballast	Distance from the bottom of the rail to the top of the ballast. If this value is equal to the tie plate thickness, then the top of the ballast is flush with the tops of the ties.	Numeric, non-negative	1" 25 mm
Tie Length	Length of the tie (also known as sleeper).	Numeric, non-negative	8.5' 2.59 m
Tie Depth	Depth of tie	Numeric, non-negative	7" 178 mm
Minimum Ballast Depth	The minimum vertical distance between the bottom of the tie and the top of the subballast. The location of this minimum distance changes at different stages in cant. See Behavior below.	Numeric, non-negative	12" 305 mm
Ballast Shoulder Width (Left and Right)	The distance from the end of the tie to the beginning of the ballast side slope.	Numeric, non-negative	12" 305 mm
Ballast Side Slope (Left and Right)	The slope of the side of the ballast material. The slope of the top of the ballast material matches the slope of the tie that results from cant.	Slope, non-negative	2:1
Subballast Depth	The depth of the subballast material	Numeric, non-negative	8" 203 mm
Subballast Top Slope (Left and Right)	The top slope of the left and right sides of the subballast with the centerline of the subassembly as the hinge point.	Slope, non-negative	40:1
Subballast Side Slope	The slope of the side of the subballast material.	Slope, non-negative	2:1
SubBase Extension	The distance from the toe of the subballast material to the beginning of the side slope of the subbase material	Numeric, non-negative	0.5 ft 0.15 m
SubBase Slope	The slope of the side of the SubBase material.	Slope, non-negative	1:1
SubBase Depth	The depth of the SubBase material	Numeric, non-negative	1 ft 0.30 m
Soil Fill Depth	The depth of the Soil Fill material	Numeric, non-negative	1 ft 0.30 m
Soil Fill Slope	The slope of the side of the Soil Fill material.	Slope, non-negative	1:1
Soil Fill Extension	The distance from the toe of the subbase material to the beginning of the side slope of the Soil Fill material	Numeric, non-negative	0.5 ft 0.15 m
Omit Rails	Prevents the rail points, links, and shapes from being drawn.	Yes/No	No
Omit Tie	Prevents the tie points, links, and shapes from being drawn.	Yes/No	No
Omit Ballast	Prevents the ballast points, links, and shapes from being drawn. If this option is set to Yes then the subballast is also not drawn.	Yes/No	No
Omit Subballast	Prevents the subballast points, links, and shapes from being drawn. If the Omit Ballast option is set to Yes then the subballast is not drawn regardless of this setting.	Yes/No	No
Omit SubBase	Prevents the subbase points, links, and shapes from being drawn. If the Omit Ballast or subballast option is set to Yes then the Sub Base is not drawn regardless of this setting.	Yes/No	No
Omit Soil Fill	Prevents the soil fill points, links, and shapes from being drawn. If the Omit Ballast, subballast, or subbase option is set to Yes then the soil fill is not drawn regardless of this setting.	Yes/No	No

Target Parameters

This section lists the parameters in this subassembly that can be mapped to one or more target objects. For more information, see To Specify Corridor Targets.

Parameter	Description	Status
RightSideOffset	Right Side Offset	Optional
RightSideElevation	Right Side Elevation	Optional

Runtime Logical Assignments

None.

Output Parameters

None.

Behavior

This subassembly works in multi-track situations in conjunction with the Internal Multi Track Subassembly and/or the Right Hand Multi Track Subassembly. With these subassemblies, each rail line has its own alignment and profile. Place this subassembly on the left hand alignment and profile. Control the right edge location of the subassembly with the input parameters or with the target parameters provided. Target lines between the left hand alignment and the internal rail alignments.

When you apply rail cant information to the alignment baseline, the rails rotate accordingly. The point about which they rotate depends on the Pivot Method setting contained in the cant information for the alignment. If you set a Pivot Method to Low Side Rail, then the rail on the inside of the curve is held at track elevation and the elevation of the outside rail is adjusted an amount equal to the cant value.

If you set the Pivot Method to High Side Rail, then the rail on the outside of the curve is held at track elevation and the elevation of the inside rail is adjusted an amount equal to the cant value.

If you set the Pivot Method to Center Baseline, then both rails are adjusted an amount equal to half the cant value, the outside rail upward and inside rail downward.

The Minimum Ballast Depth value applies at the location of the minimum clearance between the tie and subballast. The Subballast Top Slope parameter independently controls the subballast top slope . The Baseline to Subballast Crown parameter controls the location of the subballast crown.

Rail Detail

The rail shape used in this subassembly is a simplified approximation of industry standard rail shapes and dimensions. Rail Head Width, Rail Depth, and Rail Base Width are available as input parameters and are used to derive the remaining approximated dimensions.

Layout Mode Operation

In layout mode the subassembly displays the links comprising the rails, tie, ballast, subballast, and side slopes.

Point, Link, and Shape Codes

The following table lists the point, link, and shape codes for this subassembly that have codes assigned to them. Point, link, or shape codes for this subassembly that do not have codes assigned are not included in this table.

Point, Link, or Shape	Code	Description
P1, P4-P21	Rail	Rail
P2	Cl_Rail	Centerline of Rail
P3	Gauge_Line,Rail	Gauge line (inside edge of top of rail)
P28-P32, P60	Tie	Tie
P45, P54-P55, P47, P71-P72	Ballast	Ballast
P50, P53, P73	Subballast	Subballast
P63, P65, P74	SubBase	SubBase
P68-P70, P75	SoilFill	SoilFill
L1, L2	Top_Rail, Rail	Top of rail
L3-L28	Rail	Rail
L29-L33, L65-66	Tie	Tie
L40-L41, L44, L55-L56, L79, L88	Ballast	Ballast
L57, L60-L62, L80	Subballast	Subballast
L70-L72, L81	SubBase	SubBase
L76-L78, L82	SoilFill	SoilFill
S1, S2	Rail	Rails
S3	Tie	Tie
S4	Ballast	Ballast
S5	Subballast	Subballast
S6	SubBase	SubBase
S7	SoilFill	SoilFill

Left_Hand_Multi_Track