Model Assumptions & Equations

These estimates are simplified teaching models for comparing route options. They support engineering judgement; they are not a detailed rail operations model or a construction cost estimate.

1. Cost Model Assumptions

2. Grade Penalty (Slope)

Applies to Normal Track and Bridges. Tunnels are exempt in this simplified model.

$$ M_{grade} = e^{(k_{grade} \cdot S_g \cdot Grade\%/100)} $$

3. Curve Penalty (Tight Turns)

$$ Tightness = \max(0, \frac{R_{min}}{R_{actual}} - 1) $$ $$ M_{curve} = e^{(k_{curve} \cdot S_c \cdot Tightness)} $$

4. Elevation Penalty (Tunnels Only)

$$ ExcessE = \max(0, Elev_{max} - E0) $$ $$ M_{elev} = e^{(k_{elev} \cdot \frac{ExcessE}{100})} $$
Penalizes deep tunnels under high mountains (Threshold E0).

5. Length Penalty (Long Bridges/Tunnels)

$$ ExcessL = \max(0, Length_{structure} - L0) $$ $$ M_{len} = 1 + c_{type} \cdot k_{len} \cdot \frac{ExcessL}{1000} \; (capped) $$
Long continuous structures attract a capped length premium rather than an unbounded exponential penalty (Threshold L0).

6. Travel Time Assumptions

$$ v_{max} = \frac{Speed_{km/h}}{3.6} $$ $$ d_{accel} = \frac{v_{max}^2}{2a}, \quad d_{decel} = \frac{v_{max}^2}{2b} $$ $$ T_{total} = T_{run} + Stops \cdot Dwell $$

Where \(a\) is acceleration, \(b\) is deceleration, and dwell is entered in minutes per intermediate stop.

Acknowledgement
Author: Jiale Zhu
Original idea: Prof. David Airey
Thanks to Prof. David M. Levinson, who provided valuable insight and feedback. Thanks to Alireza Soltani, who provided valuable feedback. Thanks to Joanna Rozario, who test-run this tool and gave feedback.

Quick Start Guide

1. Plan Route
Click the map to place broad control points first. Use Terrain/Rail for contours and rail context. 3D Shade turns on with Terrain/Rail, but can be switched off separately if the map becomes too busy. Each new point is limited to 20 km from the previous selection.

2. Build Route
When the corridor shape is reasonable, switch to Build Route. Choose a construction type, then click route segments to assign normal track, bridge, tunnel, or cut/fill. Use Range Fill for a continuous bridge, tunnel, or earthworks section.

3. Review Issues
Use the warning cards and profile view to identify steep grades, tight curves, vertical mismatch, or environmental concerns. A red section means the route needs a design response or explanation.

4. Compare Options
Save snapshots for at least two route options. Compare cost, length, cut/fill, max grade, estimated travel time, and the planning trade-offs behind each option.

5. Export
Export the route, profile, and session once the option is stable enough to discuss in your group.

HSR Alignment Studio

Engineering Command

Build a corridor, test constraints, and compare defensible route options.
Theme

Plan Route

Click the map to add control points. Drag markers to reshape the route and right-click a point to delete it.

Build Route

Plan Route active. Click the map to add points, then switch to Build Route when the corridor is ready. Build tools, including Range Fill, will appear below.

Route Assumptions

Required Radius: ~4090 m
Estimated Travel Time
Assumes evenly spaced stops, acceleration from each departure, braking into each stop/end, and dwell time at intermediate stops.

Exports & Session Data

Session files restore the route, painted structures, design settings, and local KML contours.
Fetching Elevation...
Track
Bridge
Tunnel
Cut
Fill
Issue

Decision Dashboard

Length
0 km
Cost
$0 M
Max Grade
0 %
Min Radius
-
Est. Time
0 min
No route yet Start with a broad corridor, then use the dashboard to explain cost, constructability, and route trade-offs.

Warnings 0

No critical issues detected.

Option Comparison

No saved options yet.

Cost Estimator ($AUD)

Normal ($/100m):
Bridge ($/100m):
Tunnel ($/100m):
Cut/Fill ($/100m):
Multipliers (Exponential k):
Tunnel Parameters:
Bridge Parameters:
Total: $0 M
Top Cost Drivers (per 100m):

Alignment Profile (Vertical Exaggeration)