THE INVESTIGATION OF DERAILMENTS AUGUST 2014 INDIAN RAILWAYS INSTITUTE OF CIVIL ENGINEERING, Pune 411001 i ii FOREWORD TO THE FOURTH EDITION It has been an endeavour of IRICEN to publish books containing the latest information on subjects useful for the railway engineers. This book ‘The Investigation of Derailments’ published by IRICEN has served the objective for more than three decades. Railway men of various disciplines have immensely benefited from the contents of this book. Third edition of the book was published in 2007. Since then, some new type of rolling stock have been introduced. Also, there have been changes in maintenance practices for rolling stock and track.IRICEN is bringing out this Fourth Edition of the book, incorporating these changes. I hope that the railway men would find this revised edition a useful source of the required information for a scientific investigation of derailments. Pune, Vishwesh Chaube August, 2014 Director IRICEN, PUNE iii PREFACE TO THE FOURTH EDITION The first edition of the book ‘The Investigation of Derailments’ was published in May, 1981 by Indian Railways Institute of Advance Track Technology (Presently known as Indian Railways Institute of Civil Engineering), Pune. Second edition of the book was published in May, 1995, in which a new chapter, incorporating case studies was added. Third edition of the book was published in March, 2007. In this edition, information related to CASNUB bogies, Fiat Bogies and new types of locomotives was incorporated. Subsequent to the publication of the 3rd edition of the book, significant developments have taken place relating to rolling stock running on the Indian Railways network .Some new type of rolling stock have been introduced. Population of some of the newer rolling stock has significantly increased while some of the older rolling stock have significantly reduced in number, or have been totally phased out. Also, there have been changes in the maintenance practice of some of the rolling stock system. Therefore, a need has arisen for revision of the book. In this edition, some significant additions have been made. These include, Influence of Angle of Attack on the limiting valueof Y/Q and Mechanism of re-distribution of wheel load in a bogie in Chapter 1, ‘Theoretical Background’. In Chapter 3, ‘Rolling Stock Features and Defects’, systems of Air Spring, Hydraulic Shock Absorber, and Bogie Rotation have been added. In Chapter5,‘Coaching Stock’, various components of ICF All- coil Bogie have been elaborated and description of various components of LHB FIAT Bogie have been added. Chapter 6 on Locomotives has been re-written. Locomotives have been grouped based on bogie design, for the ease of comprehension at the field engineers level. New bogies, namely, High Adhesion bogie, Flexi-coil Mark I bogie, High Tensile Steel Cast (HTSC) GM bogie, Bo-Bo Flexi-coil Fabricated bogie and Co-Co Flexi-coil Fabricated bogie have been added. In Chapter 9, ‘Case Studies’, some good iv case studies related to interaction between track – rolling stock defects causing derailment as well as signaling system defects leading to derailment have been added. I am thankful to the faculty and staff of IRICEN who have contributed immensely to the publication of this book. I am grateful to Director, IRICEN for his encouragement and guidance in bringing out this publication. Although care has been taken to include details as per authentic and latest reference in this publication, still there may be some errors. I would be thankful to the readers for their suggestions, which may be sent to IRICEN at [email protected]. These would be taken into account while preparing the next version of the book. Pune Nilmani August, 2014 Professor/Track – 1 IRICEN v PREFACE TO THE THIRD EDITION Second edition of the book “The Investigation of Derailments” was reprinted in 2001. It was very popular among field engineers and became out of stock in due course of time. Therefore, the third revised and enlarged edition has been brought out to fulfill the continuous demand for the book. Information pertaining to new goods and coaching stock has been added in this edition, which will be very useful to field engineers. Although every effort has been made to bring out latest and present the book in error free manner, yet if there is any suggestion or discrepancy, kindly do write to us. Shiv Kumar Director, IRICEN vi PREFACE TO SECOND EDITION Investigation of the factors leading to derailment constitutes by itself a sailent facet of the accident management. The purpose of investigation is not only to pinpoint the cause of derailment but also to document the lessons learnt to avoid recurrence of lapses. This book published by IRICEN served this objective for more than a decade and railway men of all disciplines have been immensely benefited by the contents of this book. With changes in track technology and with the introduction of new types of rolling stock, need had arisen to update the information. I am glad IRICEN is accordingly bringing out the revised edition of ‘The Investigation of Derailment’, also incorporating case studies as a fresh chapter. I hope this enlarged edition will be even more useful to the Railwaymen of all departments, with the ultimate goal of total prevention of accidents. Raj Kumar Member Engineering Railway Board New Delhi vii FOREWORD TO SECOND EDITION A derailment costs money, anguish to users and possible loss of life. For preventing its recurrence therefore, no effort is too much. Expressing in a nutshell, concern of a permanent way man in regard to a derailment is : - to rescue, repair and restore - to establish the cause by joint investigation - to use the resultant information to guide preventive or corrective efforts. Unless the cause is obvious, e.g. a tree or a boulder fallen on the track, breach, washaway, formation failure, etc., the task of investigating and determining the cause of a derailment is a formidable one, as a large number of variables are involved. It is recognized that investigative competence cannot alone come from books or teaching, it is mainly derived from the practical field experience. However, the former serves as important adjunct to this total experience by enhancing our knowledge of critical factors associated with derailments. This booklet strives to help achieve this objective. The booklet has been divided into 6 chapters: - Theoretical background - Site investigation - Rolling stock suspension systems and defects - Track defects - Operating features. - To sum up… The last chapter, condensing the sailent aspects of derailment mechanics, embodies valuble case studies. This chapter has been added in the edition of 1995, while updating the contents of the other chapters. S. GOPALAKRISHNAN DIRECTOR IRICEN 01-05-1995 viii FOREWORD TO FIRST EDITION A derailment costs money, anguish to users and possible loss of life. For preventing its recurrence therefore, no effort is too much. Expressing in a nutshell, concern of a permanent way man in regard to a derailment is: - to rescue, repair and restore - to establish the cause by joint investigation - to use the resultant information to guide preventive or corrective efforts. Unless the cause is obvious, e.g. a tree or a boulder fallen on the track, breach, washaway, formation failure, etc., the task of investigation and determining the cause of a derailment is a formidable one, as a large number of variables are involved. It is recognised that investigative competence cannot alone come from books or teaching - it is mainly derived from the practical field experience. However, the former serve as important adjuncts to this total experience by enhancing our knowledge of critical factors associated with derailments. This booklet strives to help achieve this objective. The booklet has been divided into 5 chapters : - Theoretical background - Site investigation - Rolling stock suspension systems and defects - Track defects - Operating features. Y. G. PATWARDHAN Principal Indian Railways Institute of Advance Track Technology ix CONTENTS 1. Theoretical Background 1-77 1.1 Introduction 1.2 Derailment Mechanism 1.3 Mechanism of flange climbing derailment and Nadal’s Formula 1.3.1 Play between wheel and rail and wheel angularity 1.3.2 Safety depth 1.3.3 Frictional force 1.3.4 Mechanism of Wheel Climbing Derailment 1.3.5 NADAL’S Formula 1.3.6 ( Y/Q ) ratio and shift in Point of Contact 1.4 Application of Nadal’s Formula in derailment investigation. 1.4.1 Defects and features that affect u 1.4.2 Defects and features which increase positive eccentricity 1.4.3 Defects and features which cause persistent angular running of the axle 1.5 Stability analysis by rail-wheel interaction forces 1.5.1 Chartet’s Formula 1.5.2 Further Developments 1.6 Track-Train Dynamics and its relation to rail-wheel interaction 1.7 Vehicle Oscillations 1.8 Self-excited oscillations and effect of wheel conicity 1.8.1 Amplitude of oscillation (a) 1.8.2 Frequency of oscillation (f) 1.8.3 Representation of wave motion by a point revolving in circle 1.8.4 Lateral displacement 1.8.5 Lateral oscillations & wheel tread conicity 1.8.6 Effect of rigid wheel base on self-excited oscillations 1.8.7 Lateral oscillations & effect of play between wheelset and track 1.9 Critical Speed x 1.9.1 Primary hunting 1.9.2 Secondary hunting 1.10 Cyclic track irregularities and resonance 1.11 Effect of track or vehicle twist on wheel off-loading 1.11.1 Track Twist 1.11.2 Effect of track twist 1.11.3 Springs defect 1.11.4 Torsional stiffness of vehicle underframe bogie 1.11.5 Transition portion of a curve 1.11.6 Safe limit of track twist 1.12 Lateral stability of Track 1.13 Determination of Safe Permissible maximum speed of rolling stock 1.13.1 Diesel and Electric locomotives 1.13.2 Carriage 1.13.3 Wagons 1.13.4 Locomotives, coaching stock and wagons- some general principles of comparative performance 2.