Part I — Manual Overview — Railway Ground Hazard Risk Management

I.1 Purpose of This Manual

Railway Ground Hazard Risk Management is Benesch's geotechnical reference for railroad clients. It is organized around the way ground hazards affect track. It starts with the risk framework, then the track substructure that has to be protected, then the ways that substructure fails, and then how to explore, analyze and stabilize it. Formerly titled Benesch Geo Rail, the manual was reorganized in September 2026 into nine parts.

It is written for Benesch geotechnical engineers, geologists and field staff delivering investigation, design, construction-phase and ground hazard risk management services to Class I, regional and short line railroads, and to passenger and commuter operators.

I.2 How the Manual Is Organized

Part	Title	Scope	Contents
I	Railway Ground Hazard Risk Management	About this manual and how it is organized	Part I — Manual Overview
II	Introduction to Railway Ground Hazard Risk Management	The risk framework that governs the rest of the manual	Chapter 1 — Introduction to Railway Ground Hazard Risk Management
III	Track Substructure	Ballast and subballast, subgrade, and the foundation elements beneath the track	Chapter 2 — Track Substructure: Ballast, Subballast and Subgrade Chapter 3 — Track Foundation Elements
IV	Failure Mechanisms (Triggers)	How track-support and ground-hazard failures develop and what sets them off	Chapter 4 — Failure Mechanisms and Triggers
V	Subsurface Exploration	Planning, borings, in situ testing, classification, groundwater and laboratory testing	Chapter 5 — Geotechnical Investigation Planning and Scope Chapter 6 — Borings and Sampling Chapter 7 — In Situ Testing Chapter 8 — Soil and Rock Classification Chapter 9 — Groundwater Characterization and Seepage Chapter 10 — Laboratory Testing Program
VI	Geotechnical Analysis	Bearing capacity, settlement, slope stability and seismic hazard	Chapter 11 — Foundation Engineering: Bearing Capacity Chapter 12 — Settlement Analysis Chapter 13 — Slope Stability Analysis Chapter 14 — Seismic Hazard and Liquefaction
VII	Stabilization Methods	Construction monitoring, retaining structures and ground improvement	Chapter 15 — Construction Monitoring and Field Testing Chapter 16 — Retaining Structures Chapter 17 — Ground Improvement Methods
VIII	Pavements	Pavement subgrade evaluation for yards, intermodal facilities and access roads	Chapter 18 — Pavement Subgrade Evaluation
IX	Appendix	Report preparation, templates, special provisions	Appendix E — Geotechnical Report Preparation Appendices A–C — Templates and Special Provisions Ground Improvement Technology Library — Chapter 17, Section 17.16

Where the Geotechnology for Railroaders course modules are used in this manual

Benesch’s two-day Geotechnology for Railroaders course (Modules 1–8) is the field-training companion to this manual. Its concepts, case histories, field photographs and job-aid figures are cited in the chapters below. Use the course for crews and inspectors, and this manual for the engineering basis behind it.

Table I-2. Course module to manual chapter crosswalk
Course module	Where it appears in this manual
1 — Risk Management of Geo-Hazards	Chapter 1 (risk equation, classification, case histories, stabilization program)
2 — Geology and Soil Engineering	Chapters 5, 6, 8, 10 and 18 (landforms, sampling, field identification, subgrade strength by feel)
3 — Track Substructure: Ballast and Sub Ballast	Chapters 2 and 3 (ballast functions, fouling, undercutting, sub ballast, bridge approaches)
4 — Track Drainage	Chapters 2, 3 and 9 (cardinal rules, ditches, subdrains, culvert inspection)
5 — Slides and Instabilities	Chapters 4 and 13 (downhill and uphill slide categories, the four don’ts, signs of instability)
6.1 — Slope Stabilization	Chapters 13 and 16 (berms, realignment, driven and gravity walls, soil nailing)
6.2 — Subgrade Stabilization	Chapters 11, 15 and 17 (geosynthetics, HMA underlayment, grouting, EPS, screw piles)
6.3 — Scour and Erosion	Chapter 4 (scour mechanisms, countermeasures)
6.4 — Rock Falls	Chapters 4 and 13 (rockfall strategies, incident reporting)
6.5 — Beaver Dams	Chapter 4 (BAHA program, uphill dams, rapid drawdown)
6.6 / 7.1 — Winter Problems, Spring Thaw	Chapters 2, 4 and 13 (frost heave, spring silt liquefaction, rapid drawdown)
7.2 / 7.3 — Extreme Weather, Earthquakes	Chapters 4 and 14 (event declaration, precipitation indices, seismic response criteria)

After Geotechnology for Railroaders Program, Module 1; course menu. Full reference under Supplemental Sources.

I.3 Using the Apps on a Desktop and a Phone

The manual is supported by a small set of apps on dirtbert.com. They run in any current web browser (Chrome, Edge, Safari or Firefox) on a desktop, laptop, tablet or phone. There is nothing to install and no account to create, except where a sign-in is noted below.

Table I-3. The apps, and how each one works on a desktop and on a phone
App	What it does	On a desktop	On a phone	Where your work is kept
GHRM	This manual: nine parts, 18 chapters and the appendices.	Each chapter opens with an On this page list at the left and the section train across the top. Select a section heading to open it; Expand all opens every section.	The page narrows to one column and On this page folds into a button at the top: tap it, then tap a section. Turn the phone sideways for wide tables.	Checklist ticks are saved in this browser on this device.
MINA Hazard Monitoring	Live river stage, flood, weather and tornado hazards along a railroad, with mileposts, bridges, crossings, rivers, soils and geology on one map.	Desktop layout: the map setup panel, watchlist and hazard feed sit beside the map. Open full screen fills the monitor.	Phone layout: the map fills the screen, with Map Setup, Gauges, Alerts and Status tabs along the bottom.	Nothing is stored. The layout you pick is remembered in the browser. Data loads live from public sources, so a connection is needed.
NANCY Project Workflow	One project carried through seven phases, from project set-up to the geotechnical report, with the Project Data pages: field log, boring log, laboratory results, design parameters and the two reports.	Best for entering borings, samples and test results with a keyboard. Work the phases in order; you can go back to any earlier phase.	Works for reviewing a project and for quick entries in the field. Wide tables scroll sideways.	Only in this browser on this device. Use Save file to keep a copy or move the project to another computer or phone, and Open file to load it there. Clearing browser data deletes the stored project.
GHRM Tools, Analytical Tools and the Calculator Map	Calculators, workbook guides and field forms from the Geotechnical Analysis Suite, listed by discipline or by manual chapter.	Calculators open in a new tab. The orange Analytical Tools for this Chapter card at the top of each chapter, and the orange strips inside sections, link straight to them.	Calculators work on a phone; the workbook guides read best on a larger screen.	The calculators are in the Benesch area of dirtbert.com and need a Benesch sign-in.
Ground Improvement Technology Selector	Narrows the 45 techniques of the technology library (17.16) to the ones that fit the problem and site.	Opens beside Chapter 17.	Same page, one column.	Nothing is stored.

Monitoring a railroad with MINA

Opening MINA picks the layout for the device: phones get the phone layout and everything else gets the full-screen desktop layout. To switch, use Phone view on the desktop layout or Desktop on the phone layout; the choice is remembered in that browser. Then set up the map in four steps:

Select a railroad. Its centerlines load first, and every other layer is filtered to it.
Choose a base map: dark gray, satellite imagery or USGS topographic.
Add sections: mileposts, bridges, crossings, rivers and gauges, weather hazards, flood zones, soils and geology. Layers follow the notebook numbering (01.01, 04.05 and so on); some only draw once you zoom in closer.
Launch the map. Use Find on the line to jump to a subdivision and milepost, a bridge or a crossing.

The river stage watchlist lists gauges near the line against their flood stages, and the hazard feed lists warnings on the selected network. MINA is a monitoring aid; it is not for operational dispatch decisions.

Running a project in NANCY

NANCY asks every user to read and accept the Use and Disclaimers once in each browser before its pages open; the acceptance is remembered after that. Start at NANCY and work the phases in order. Each phase page explains what is done and why, and links to the Project Data pages and the chapters of this manual that support it. Borings and samples entered on the field log appear on the boring log, laboratory results attach to their samples, and each stratum’s tested values become its design parameters. Where a property has no test, NANCY uses a conservative published correlation and marks the value as assumed.

Because the project is kept only in the browser, save a file at the end of each session. To move between a desktop and a phone, use Save file on one device and Open file on the other. Every value NANCY produces must be checked by a qualified, licensed engineer.

Keeping the apps on a phone

Open the app in the phone’s browser and add it to the home screen so it opens like an app:

iPhone or iPad (Safari): tap Share, then Add to Home Screen.
Android (Chrome): tap the ⋮ menu, then Add to Home screen.

Good candidates are MINA’s phone layout, NANCY, and the chapter you use most in the field.

Where the apps appear in this manual

Apps for this Chapter: a green card at the top of every chapter lists the apps that support it, with a line on what each one is for there.
Analytical tools: orange Analytical Tools for this Chapter card, and an orange strip inside each section a tool supports.
Checklists: sections marked with a checklist save your ticks in the browser and can be printed.

I.4 Conventions and Standards Basis

Units: English (U.S. customary) units throughout, with SI in parentheses where a source equation is SI-based.
Loading: Cooper E-80 and 286,000-lb gross rail load are the default design bases unless the client specifies otherwise.
Governing references: AREMA Manual for Railway Engineering; FRA Track Safety Standards (49 CFR Part 213) and Bridge Safety Standards (49 CFR Part 237); ASTM test methods; FHWA and USACE guidance; and each client railroad's engineering standards, which govern where they differ.
Client values: Client-specific criteria quoted in this manual are summaries for planning. Always confirm them against the client's current standard before use on a project.

Reading European (UIC / EN) railway sources alongside AREMA

Several sections of this manual draw on Profillidis, Railway Management and Engineering, which is written to UIC and European (EN) practice in metric units. AREMA and FRA remain the governing basis for North American work; the European material is included for the mechanics, the data and the design logic behind it. The terms and units below appear wherever that material is cited.

Table I-1. Terms and units used where this manual cites Profillidis
European / UIC term	North American equivalent or conversion
Sleeper	Tie (crosstie)
Track bed	Ballast + subballast together
Formation layer	Engineered top-of-subgrade layer; comparable in role to a blanket or prepared subgrade layer
Subsoil	Native or embankment fill below the formation layer
Cant / cant deficiency	Superelevation / unbalanced superelevation
Longitudinal, transverse, horizontal defect	Surface (profile), cross-level, alignment
t (metric tonne) — axle load	1 t = 2,205 lb; a 286,000-lb car on 4 axles ≈ 32.4 t/axle
kp/cm² (kilopond per cm²)	1 kp/cm² ≈ 14.2 psi
t/mm (track or layer reaction coefficient)	1 t/mm ≈ 56 kip/in.
‰ (per mille) gradient	10‰ = 1.0% grade
MGT / million tons of traffic	Same concept; UIC counts gross metric tons

UIC axle-load categories for standard gauge: A = 18 tons, B = 20 tons, C = 22 tons, D = 25 tons. Profillidis notes that standard-gauge axle loads in the USA are 28–35 tons, so European design charts calibrated to 22–25 tons sit well below North American heavy-haul loading. Rail stress is reported to grow roughly with Q³ to Q⁴ (Q = axle load), so a modest axle-load increase produces a much larger increase in fatigue.

UIC line groups (UIC Code 714R) classify lines by a fictitious daily tonnage T_th that weights freight, locomotive and speed effects: group 1 > 130,000 t/day; group 2 = 80,000–130,000; group 3 = 40,000–80,000; group 4 = 20,000–40,000; group 5 = 5,000–20,000; group 6 < 5,000 t/day. Group 4 is described as representative of most lines worldwide. Several UIC thickness and maintenance rules in this manual are keyed to these groups.

Regulation, specification, code, standard and guideline are not interchangeable. In the book’s usage, regulations and specifications are rules issued by governmental or inter-governmental bodies that impose specific instructions or methods; codes are a form of legislation defining a procedure or performance to be followed; standards are uniform criteria developed by a national or international body and are suggested rather than obligatory; guidelines are non-mandatory recommendations.

After Profillidis (2014), §7.5 (axle and traffic load), §12 footnote (definitions). Conversions added by Benesch. Full reference under Supplemental Sources.

I.5 Empirical Equations — Use and Limitations

Many values in railway geotechnical work are estimated from empirical equations: SPT and CPT correlations for strength and stiffness, index-property correlations for compressibility and permeability, rock-mass ratings, and landslide runout and rainfall-threshold relations. The manual collects 60 of them in the Empirical Equations & Correlations reference, each with its formula, original source, the data it was fitted to, and the constraints on its use.

Every equation is a statistical fit to a specific data set. Use it only within the stated materials and ranges, prefer site-specific calibration, and confirm coefficients against the cited original before relying on a result for design.

Note required when an equation is used. Wherever a correlated value appears — a calculation, a boring log, a design-parameter table, a report or a GHRM assessment — record with it:

the equation ID and source (for example, IS-02, Liao & Whitman 1986);
that the soil or rock is within the equation’s range of applicability;
that the value is correlated, not tested;
the limitation that governs (for example, “not applicable to clays”), and the test that will confirm it.

Each chapter has an Empirical Equations — Use and Limitations card listing the equations it uses, and an Empirical equation note box closes each section that refers to one. The Geotechnical Analysis Suite workflow adds the same note wherever it uses a correlation (preliminary anticipated results, assumed design parameters, the report).

Where each equation is used

ID	Equation	Family	Used in (or applies to)
IS-01	SPT energy & procedure correction	In-situ tests	Appendices; Chapter 5; Chapter 6; Chapter 11; Chapter 14; Chapter 15; Appendix E
IS-02	SPT overburden normalization (sands)	In-situ tests	Appendices (applies); Chapter 5 (applies); Chapter 6; Chapter 14; Appendix E
IS-03	Relative density of sand from SPT	In-situ tests	Chapter 6 (applies); Chapter 17 (applies)
IS-04	Friction angle of sand from SPT (Schmertmann form)	In-situ tests	Chapter 11 (applies); Chapter 16 (applies)
IS-05	Friction angle of sand from SPT (Peck–Hanson–Thornburn)	In-situ tests	Chapter 6 (applies); Chapter 11 (applies); Chapter 16 (applies)
IS-06	Friction angle of sand from SPT (Hatanaka & Uchida)	In-situ tests	Chapter 11 (applies)
IS-07	Undrained shear strength of clay from SPT	In-situ tests	Chapter 6 (applies); Chapter 11 (applies); Chapter 13 (applies); Chapter 14; Chapter 2 (applies); Appendix E; Chapter 3 (applies)
IS-08	Drained Young's modulus of sand from SPT	In-situ tests	Chapter 12 (applies)
IS-09	Shear-wave velocity from SPT	In-situ tests	Chapter 14 (applies)
IS-10	OCR of clay from SPT	In-situ tests	reference only
IS-11	Cyclic resistance ratio of sand from SPT	In-situ tests	Chapter 14
IS-12	Corrected cone resistance	In-situ tests	Chapter 7; Chapter 14; Chapter 15 (applies)
IS-13	Soil behaviour type index (normalized)	In-situ tests	Chapter 7 (applies); Chapter 14
IS-14	Undrained shear strength from CPT	In-situ tests	Chapter 7; Chapter 11 (applies); Chapter 13 (applies); Chapter 17
IS-15	Friction angle of sand from CPT	In-situ tests	Chapter 7 (applies); Chapter 11 (applies)
IS-16	Relative density of sand from CPT	In-situ tests	Chapter 7 (applies); Chapter 17 (applies)
IS-17	Preconsolidation stress / OCR from CPT	In-situ tests	Chapter 7 (applies); Chapter 12; Chapter 17; Chapter 15 (applies)
IS-18	Shear-wave velocity from CPT	In-situ tests	Chapter 7; Chapter 14; Chapter 2
IS-19	Constrained modulus from CPT	In-situ tests	Chapter 7 (applies); Chapter 12 (applies); Chapter 17 (applies)
IS-20	Hydraulic conductivity from CPT	In-situ tests	Chapter 7 (applies); Chapter 9 (applies); Chapter 17
IS-21	Soil unit weight from CPT	In-situ tests	Chapter 7 (applies); Chapter 18 (applies)
IS-22	Cyclic resistance ratio of sand from CPT	In-situ tests	Chapter 14
IS-23	Flat dilatometer (DMT) intermediate parameters	In-situ tests	Chapter 7
IS-24	OCR, K₀ and Sᵤ of clay from DMT	In-situ tests	Chapter 7
IS-25	Field vane strength correction	In-situ tests	Chapter 7; Chapter 8; Chapter 13
IX-01	Compression index from liquid limit (undisturbed)	Index properties	Chapter 5 (applies); Chapter 8 (applies); Chapter 12 (applies); Chapter 10 (applies)
IX-02	Compression index from liquid limit (remolded)	Index properties	Chapter 12 (applies); Chapter 10 (applies)
IX-03	Compression index from void ratio	Index properties	Chapter 12 (applies); Chapter 10 (applies)
IX-04	Compression index from plasticity index	Index properties	Chapter 8 (applies); Chapter 12 (applies); Chapter 10 (applies)
IX-05	Secondary compression ratio	Index properties	Chapter 12; Chapter 2 (applies); Chapter 15 (applies); Chapter 10 (applies); Chapter 3
IX-06	Normalized undrained strength from plasticity	Index properties	Chapter 13 (applies); Chapter 10 (applies)
IX-07	SHANSEP undrained strength ratio	Index properties	Chapter 13 (applies)
IX-08	Friction angle of NC clay from plasticity	Index properties	Chapter 13 (applies); Chapter 16 (applies); Chapter 10 (applies)
IX-09	At-rest earth pressure coefficient	Index properties	Chapter 7; Chapter 16; Chapter 3 (applies)
IX-10	Undrained strength from liquidity index	Index properties	Chapter 8; Chapter 18 (applies); Chapter 10 (applies)
IX-11	Hazen hydraulic conductivity	Index properties	Chapter 9 (applies); Chapter 17 (applies); Chapter 10 (applies)
IX-12	Chapuis hydraulic conductivity	Index properties	Chapter 9 (applies)
IX-13	Small-strain shear modulus (Hardin)	Index properties	Chapter 7; Chapter 14 (applies); Chapter 2 (applies); Chapter 10 (applies)
RK-01	Rock Mass Rating (RMR₈₉)	Rock mass & rockfall	Chapter 5 (applies); Chapter 8
RK-02	Rock mass quality (Q-system)	Rock mass & rockfall	Chapter 8
RK-03	RMR–Q conversion	Rock mass & rockfall	Chapter 8 (applies)
RK-04	RQD from volumetric joint count	Rock mass & rockfall	Chapter 6 (applies); Chapter 8 (applies)
RK-05	GSI from RMR₈₉	Rock mass & rockfall	Chapter 8
RK-06	Slope Mass Rating	Rock mass & rockfall	Chapter 13 (applies); Chapter 1 (applies); Chapter 4 (applies)
RK-07	Generalized Hoek–Brown criterion	Rock mass & rockfall	Chapter 11 (applies); Chapter 13 (applies)
RK-08	Rock mass deformation modulus	Rock mass & rockfall	Chapter 14
RK-09	Joint shear strength (Barton–Bandis)	Rock mass & rockfall	Chapter 13 (applies)
RK-10	UCS from point load index	Rock mass & rockfall	Appendices; Chapter 5; Chapter 6; Chapter 8 (applies); Chapter 18; Chapter 2; Chapter 10
RK-11	Rockfall shadow angle	Rock mass & rockfall	Chapter 1 (applies); Chapter 4 (applies)
RK-12	Rockfall Hazard Rating System scoring	Rock mass & rockfall	Chapter 1 (applies); Chapter 4
LS-01	Reach angle (Fahrböschung) vs. volume — rock avalanches	Landslide & debris flow	Chapter 1 (applies); Chapter 4 (applies)
LS-02	Reach angle vs. volume — all landslide types	Landslide & debris flow	Chapter 1 (applies)
LS-03	Debris-flow travel distance	Landslide & debris flow	Chapter 1 (applies); Chapter 4 (applies)
LS-04	Debris-flow peak discharge	Landslide & debris flow	Chapter 1 (applies)
LS-05	Debris-flow inundation area (LAHARZ-type)	Landslide & debris flow	Chapter 1 (applies)
LS-06	Debris-flow velocity from superelevation	Landslide & debris flow	Chapter 4 (applies)
LS-07	Landslide volume from area	Landslide & debris flow	Chapter 1 (applies)
LS-08	Rainfall intensity–duration threshold (Caine)	Landslide & debris flow	Chapter 1 (applies); Chapter 4
LS-09	Rainfall intensity–duration threshold (global update)	Landslide & debris flow	Chapter 1 (applies); Chapter 4 (applies)
LS-10	Newmark sliding displacement (regression)	Landslide & debris flow	Chapter 14; Chapter 1 (applies); Chapter 4 (applies)

Supplemental Sources

Sections on this page marked “After Profillidis (2014)” draw on the document below. Text is summarized or paraphrased; tables are transcribed or reproduced with their original source noted; figures and photos are reproduced from the cited document for internal reference use. Consult the original document before relying on a value for design.

Profillidis, V. A. (2014). Railway Management and Engineering, 4th ed. Farnham, UK: Ashgate. Chapters 7–9, 11–13, 16–17, 20 and 22 (track system, mechanical behavior of track, subgrade, sleepers, ballast, transverse effects, maintenance, slab track, electrification foundations, safety)
Benesch. Geotechnology for Railroaders Program, Modules 1–8 (two-day training course reference: risk management, geology and soils, ballast and sub ballast, drainage, slides, slope and subgrade stabilization, scour, rock falls, beaver dams, winter problems, spring thaw, extreme weather, earthquakes). Field photographs and figures from the course; slope stabilization process slides adapted from material by D. Colwell

Author and Sources

Authors: Daniel P. Colwell and Mario Ruel. This part was written and compiled by Daniel P. Colwell and Mario Ruel for Railway Ground Hazard Risk Management.

Technical content is drawn from the published sources below, and credit for that material belongs to their authors and publishers. Tables, equations and figures taken from a specific source are also cited where they appear.

This part summarizes and organizes material from the chapters that follow; see the Author and Sources section at the end of each chapter for the works cited.