Rail Track Geometry Measurement
Track geometry is what keeps a train on the rails. KHEERAN’s continuous geometry measurement system captures all six parameters at closely spaced intervals — producing a complete picture of your track’s condition, exception list, and Track Quality Index across your entire network in a single campaign.
Six Parameters Measured Continuously
- Gauge — inner rail face separation 5/8″ below the running surface. Standard: 4 ft 8½ in (1,435 mm). Flags both narrow gauge (flange climb risk) and wide gauge (instability/wheel drop)
- Horizontal Alignment — lateral deviation via mid-chord ordinate (MCO) on 31-ft and 62-ft chords, catching kinks, weld misalignment and wave irregularities
- Vertical Profile — up-down deviation from smooth reference; dominant contributor to ride quality and fatigue damage
- Cross-Level — height difference between left and right rails; on curves confirms superelevation matches posted speed
- Twist (Warp) — rate of cross-level change over 31 ft; consistently the most derailment-significant geometry parameter in FRA defect statistics
- Curvature — degree of curve at each position; validates that superelevation and speed are compatible with actual measured alignment
Standards & Compliance
KHEERAN evaluates geometry against three regulatory frameworks:
- FRA 49 CFR Part 213 (USA) — Track Classes 1–6, exception list in ATIP TGIR format including milepost, peak value, exception length, Limiting Class and Posted Class. Two-class drops flagged as safety-critical
- Transport Canada O-0-93 — Rules Respecting Track Safety for Canadian operations
- EN 13848 series (International) — Alert Limits, Immediate Action Limits and Track Quality Numbers for European and international railway clients
Track Quality Index (TQI)
Individual exceptions locate specific defects. TQI rates the overall roughness of each 528-foot segment using the FRA space-curve method — the difference between the measured geometry path length and an ideal track path. TQI is computed for five channels (cross-level, left/right profile, left/right alignment) and compared against the national average for your track class. A segment rated “poor” within its class warrants priority attention.
Run-over-run comparison from repeat surveys identifies segments where TQI is declining fastest — enabling maintenance to be prioritised to the highest-rate-of-change sections, not just the worst current performers.
Root-Cause Correlation with GPR
KHEERAN pairs geometry data with GPR substructure data in a combined report. A geometry exception at a chainage where GPR shows heavily fouled ballast or a trapped-water pocket is flagged as a drainage or undercutting problem — not a surfacing problem. Maintenance budgets go to the right intervention the first time, not to tamping that re-emerges within months because the root cause wasn’t addressed.
Report Format
- Exception list in FRA ATIP TGIR format (or EN/TC equivalent)
- TQI summary by segment and track class comparison
- Run-over-run delta maps (repeat surveys)
- Combined GPR + geometry correlation report (integrated campaigns)
- GIS-compatible chainage files