ATES – Helping Railways in mechanical rolling stock inspection

The objective of the system is to determine any surface abnormalities of the wheel that can be detected using high resolution images of the wheel and high density 3D data of the wheel surface.

Representational Image
Representational Image

Train Technology


Indian railways have entered into a TOT agreement for manufacture of LHB coaches from M/S LHB-Alstom Germany. Now these coaches are being manufactured in India under the Transfer of Technology. These are superior coaches with respect to passenger comfort, higher safety, speed potential, lower corrosion and better aesthetics.

With the recent plan of Indian Railways to ramp up LHB coach production and rapid replacement of old design of ICF coaches by LHB design of coaches, there is need to upgrade the maintenance facilities in Coaching Depots and make use of technology available for Coach maintenance. This will also help in improved detection of defects during train examination and possibility of reduction in examination time of coaching rakes to enable maintenance depots to handle higher number of trains examined within the existence infrastructure. This will also ease out those coaching depots not having adequate pit examination capacity to some extent by saving in manpower deployed, pit line examination and maintenance time required for Coaching Rakes.

Maintenance schedules of LHB coaches are governed by guidelines issued by Railway Board, RCF, RDSO and CAMTECH from time to time. The present maintenance regime has evolved based on the performance of LHB coaches from field and periodic review of maintenance schedules and instructions. In the present setup, primary maintenance time of 6 hours is prescribed for coaching rake examination.

With introduction of higher speed of 160 and 180 kmph trains on Indian Railways, there is need to incorporate technological aids in train examination and remove existing limitations and bottlenecks in existing coaching depots.

Historical Background

Present system of coaching rake examination has evolved from conventional four-wheeler coaching stock and later with ICF design of coaches. With the introduction of imported LHB coaches in the year 2000 and indigenously manufactured series production, number of latest and sophisticated technology items have been introduced on Indian Railways. LHB coaches are gradually replacing and phasing out ICF design of Coaches.

Examination and maintenance of LHB rakes has been introduced in existing coaching maintenance facilities by incremental augmentation within the existing infrastructure both in coaching depots and workshops. There has not been any major technological input in terms of machinery and plant, automation detection systems and re-skilling of maintenance staff in coaching depots. Maintenance schedules for LHB coaches have been devised within the existing maintenance facilities constraints. Suffice it to say that with the continual induction of the sophisticated, computer and IT based technology at a fast pace the existing norms of maintenance of LHB and other advanced coaching stock need to be immediately revisited and upgraded.

With the rapid replacement of ICF coaches with LHB coaches and Indian Railways plan to phase out ICF coaches, there is an urgent need to equip all coaching depots, sick lines, pit lines, examination yards with modern and automated train examination system consisting of state-of-the-art inspection and measurement systems on Indian Railways.

The various modes of automatic train inspection and measurements systems

Wheel Profile Measurement System

Automatic wayside system measures the wheel profiles of moving trains. These systems are used to inspect wheels for preventative maintenance, maintenance scheduling, derailment prevention, and to reduce track and rail damage caused by excessively worn wheels. 

It is rugged system that operates in harsh environments as well as workshops, depots, and yards. Capable of operating without human intervention for extended periods. Wheel diameter measurements at high speeds of up to 140 km/h is possible. The other variants allow for operation in low speed for specific conditions and provide a variety of different measurements. 

It is an effective system and quickly pays for itself by improving wheel maintenance practices and eliminating derailments due to worn wheels. It increases the efficiency of wheel maintenance by identifying proactive maintenance practices based on the application of wheel wear rates and early wheel defect detection. 

Wheel Tread & Surface Inspection System

The system is automatic non-contact optical wheel surface inspection unit that inspects wheel tread surface, flange, and plate areas at mainline operational speeds. Visual inspection of complete wheel tread and flange surface using optical imaging and 3D laser scanning is possible. The objective of the system is to determine any surface abnormalities of the wheel that can be detected using high resolution images of the wheel and high density 3D data of the wheel surface.

State of art digital imaging and laser scanning technology for maximum data density, accuracy, and efficiency. Series of sophisticated image processing algorithms help to assess wheel tread and flange surface condition from acquired multispectral multi-illumination images. It can operate at mainline speeds up to 100 km/h for greater utilization. It can also operate at very low speed, where traditional ‘contact’ impact and force measurement-based systems fall short of detecting wheel surface problems such as flats due to restrictive speed limitations.

Brake Shoe (Block) Measurement System

Brake Shoe measurement system inspects brake shoes (blocks) at mainline operational speeds. This system is vision-based and uses a multi-camera high-speed imaging unit to take multiple images of every brake shoe for inspection and measurement. It can provide a complete and reliable assessment of the brake shoe (block) condition by highlighting obvious shoe defects. The system is fully automated and suitable for extreme conditions—indoors and out. Enclosures are installed on two short towers, one on each side of the track, mounted on two concrete or steel footings. Cameras and illumination systems are installed at a safe distance from the center of the track. Each brake shoe is viewed by two cameras, to provide a complete and reliable assessment of the brake shoe condition. Brake shoes are viewed from top and bottom perspectives. Acquired images are processed by a set of sophisticated image processing algorithms. The imaging system and processing algorithms are insensitive to ambient light conditions and can operate day or night. Brake shoe data is integrated into the data management system which gives web-based access to data including images.

Brake Pad Measurement System

Brake Pad automatic brake pad measurement system operates on passing trains at mainline operational speeds. It is a machine vision system which uses a high-speed digital imaging system to acquire images of every brake pad for inspection and measurement.

Brake pads are viewed from the bottom and the acquired images are processed by a set of sophisticated image processing algorithms. The imaging system and processing algorithms are insensitive to ambient light conditions and can operate day or night. It utilizes both laser based structural light and other illumination to produce several images concurrently for reliable measurements.

Brake Disc Profile MeasurBrake Disc Profile Measurement System

Automatic wayside brake disc inspection system operates on passing trains at mainline operational speeds. It is a machine vision system which uses a high speed digital imaging system to acquire images of every brake disc for inspection and measurement. Brake discs are viewed from the bottom and acquired images are processed by a set of sophisticated image processing algorithms. The imaging system and processing algorithms are insensitive to ambient light conditions and can operate day—or night. The system utilizes both laser based structural light and other illumination to produce several images concurrently for reliable measurement and inspection.

Wayside Truck (Bogie) Inspection System

Wayside truck (bogie) inspection system operates on passing trains at mainline operational speeds. It is a vision based system which uses high-speed and high-definition imaging to provide high resolution images of every truck for inspection and measurement.

Many truck related defects can cause serious short term and long terms problems and possible derailments. For a reliable and dependable inspection every truck is viewed from at least two angles—top and bottom. This system can inspect many features of bogies including fasteners, side frame condition, bearings and related components, friction wedges, springs, and more. Alarms are generated when issues are detected. Examples are excessive wedge rise, spring condition to find missing and broken springs, and spring compression to detect imbalanced loads.

Brake Air Hose Inspection System

Brake air hose inspection system operates on passing trains at mainline operational speeds. A vision based system uses a high-speed and high definition imaging system to provide high resolution images of every air hose arrangement for inspection and measurement.

Air hose arrangements and their diagnosis is complex and an automated system is highly beneficial as air hose separation is one of the leading causes of train stoppage in passenger and freight operations. It provides automated alarms based on the condition of the air hose arrangement and detects the ones that have the highest probability of separation.

It is designed to inspect many conditions of the air hose assembly and can detect defects like peaked air hose coupling, air hose height, air hose angle, coupling position, and more.

F-Type Coupler Securement Inspection System

It is a machine vision wayside detection system that detects defects in F-type coupler securement mechanisms. It utilizes high-speed digital line imaging cameras to acquire multiple images of every coupler pin securement for inspection. The system works at mainline speeds, even in tough environments, day or night. For F-type couplers, the system inspects the coupler vertical pin carrier plate, securement, and the corresponding fasteners. Different types of F-type securements, including ones with cushioning units can also be handled as well.

If the coupler securement fails during train operation there is a high probability that the coupler will “pull out” of the car in a draft situation. In most cases this will result in the coupler falling between the cars and into the gauge of the track. If the train is operating at mainline speeds this can result in a derailment. The system is installed on steel ties (sleepers). Cameras and the illumination system are enclosed in sealed steel boxes mounted on the gauge side of the supplied steel tie (sleeper). The securement component images are analyzed for possible failure, deformation, and missing fasteners, and plates.

E-Type Coupler Securement Inspection System

It is an automatic wayside detection system that is designed to inspect E-Type coupler securement components at mainline speeds. It uses a high-speed strobe digital imaging system to acquire multiple images of every cross key (draft key) and the surrounding area for inspection. The system is used to inspect the cross key and its securement mechanism. Failure of such securement parts is a source of delay and derailments. It operates on passing trains at mainline operational speeds up to 85 mph (140 km/h). All cross keys are imaged from both front and back—including the area under the center sill for proper E/F coupler classification.

The system’s processing algorithm classifies couplers into E and F types before the plate processing and only E-Type couplers are inspected. Cameras and illumination component are enclosed in sealed boxes mounted on the gauge side of the steel tie (sleeper). Images are analyzed for the existence of the cross key and its securement components.

Car Undercarriage Inspection System

Car undercarriage imaging and automated inspection system produces high quality images of the structural components of Coaches/Wagons/EMU/MEMU/DEMU and locomotives at mainline operational speeds. The system is highly effective for the inspection of all undercarriage components for passenger and freight trains.

It automates the inspection of undercarriage components such as brake rigging components, center and side sill, couplers and coupler components, jacking plate, and more. The inspection of car (wagon) components which are only visible from the bottom has always been a challenge for railway operators. The system operates with line scan imaging technology and produces high resolution images of virtually all visible components under the car. It is installed under the track and is housed within steel tie (sleeper) structures.

It uses multiple cameras to capture different areas of the car undercarriage with different angles of view. Specially designed lighting systems are deployed with the system to provide ample illumination and withstand the harsh railroad track environment.

Wayside Full Train Imaging, Inspection and Measurement System

It is a full scale train imaging, 3D scanning, and inspection system consists of multiple imaging and scanning units that provide images of the train at mainline speeds with high resolution. The system is designed to provide data of all externally visible components of a rail vehicle. The images and data are then assigned to individual cars based on the AEI data so that car components are then ready for viewing and analysis. The system uses multiple sensors and algorithms to pinpoint axle position, car beginning and car end positions, car components such as safety appliances, hand brake wheels, car identifiers, load limit identification, reflectors, car body condition, structural gauge and high-wide load detection, car load profile, load securement conditions, load carry back detection, etc. The train viewing software can be used to perform a complete virtual train visual inspection as well.

Angle of Attack & B2B Measurement System

Angle-of-attack (AOA) measurement system is designed to measure AOA on both wheels of a wheelset simultaneously. It provides a reliable AOA measurement as track fluctuations due to dynamic loads do not affect where the measurements are performed. It also accurately measures back-to-back distance of wheel sets with multiple measurements from both wheels of an axle. It is also capable of measuring tracking position and axle back-to-back dimension.

In addition to above, following systems are also recommended to automate the train examination activities.

  • Fully automatic single car test rig
  • Sliding Wheel Detection
  • High Speed Train Thermal Imaging
  • Roller bearing acoustic examination
  • Roller bearing thermal scanning examination
  • Hot Axle wheel detector
  • Automatic in-motion train washing system (ACWP)
  • Bio toilet cleaning, maintenance and Bio-toilet evacuation machine
  • Sewage/Waste disposal system and Water recycling plant
  • Integration of LHB coach brake system with real time online monitoring
  • for performance detection of Brake operation and release.

Metro Rail Continuous Automatic Train Control System 

Continuous Automatic Train Control System 

  1. The Metro Rail Continuous Automatic Train Control System of working shall be adopted on the Metro Railway for the movement of trains between stations and between depot and the mainline.
  2. The Continuous Automatic Train Control system works on the principle of target speed and target distance with Cab Signalling by means of continuous transmission between trackside and train through suitable approved means, ensuring safe movement of all trains under all operating conditions by continuously generating a maximum safe speed.
  3. The limit of movement authority shall be the farthest point to which the train may safely proceed taking into account margins for error in speed and distance measurement, calculating braking distances, and the equipment reaction times.
  4. The maximum safe speed shall be the maximum speed at which the train is permitted to travel without intervention by the train control and signalling system and it shall be continuously calculated in such a manner that permanent speed restrictions, the speed limits for the type of train and temporary speed restrictions shall not be exceeded and the train shall always stop without passing the limit of movement authority.
  5. The Continuous Automatic Train Control system will provide the following modes of train operation, namely:
  1. Automatic Mode, where provided.
  2. Automatic Reversal Mode (if provided).
  3. Coded Manual Mode
  4. Restricted Manual Mode.
  5. Cut Out Mode, and
  6. Run On Sight Mode

Metro Rail Continuous Automatic Train Control System Automatic Mode 

Automatic Mode

  1. In the Automatic Mode, the train shall operate without intervention by the Train Operator except closing of train doors and starting from a station stop and it shall operate under the supervision and control of Automatic Train Protection functions.
  1. In Automatic Mode, the train control and the signalling system shall–
  1. Accelerate and decelerate the train by applying traction power, coasting and applying and releasing brakes.
  2. Automatically control speed, acceleration, and stop the train at stations.
  3. Provide all indications necessary to operate the train.
  4. Determine continuously the maximum safe speed and limit of movement authority.
  5. Prevent movement of the train in excess of the maximum safe speed and limit of movement authority.
  6. Open train doors on the correct side when the train is docked if permitted by the Automatic Train Protection door release and the platform screen doors, where provided, open automatically on the correct side;
  7. Prevent the train from starting if train doors, or the platform screen doors where provided, are not detected closed;
  8. Train re-starting from a signal stop shall be automatic; and
  9. Train starting or re-starting from a station stop shall be initiated by the Train Operator. 

Automatic Reversal Mode 

  1. This mode, where provided, is used to reverse the running direction of a train automatically in areas of the section specifically defined in the special instructions which are possible only at specified track circuits of a station when the train is at standstill.
  2. The transition from Automatic Mode or Coded Manual mode to Automatic Reversal mode is initiated automatically upon receiving the request for reversal operation from Automatic Train Supervision and has to be acknowledged by the Train Operator by pressing the Automatic Reversal button at standstill.
  3. The onboard Automatic Train Protection unit of the leading cab activates the unit at the trailing end on arrival at a station if a reversal operation is requested by Train Operator.
  4. The train-borne Automatic Train Protection unit shall return from Automatic Reversal mode to Coded Manual mode once the reversal operation has been carried out successfully and the Train Operator has unlocked the new leading cab for further running. 

Coded Manual Mode 

  1. In Coded Manual Mode the train shall be driven by the Train Operator, obeying Cab Signals.
  2. In Coded Manual Mode, the train control and signalling system shall-
  1. Provide cab signals and all other indications necessary to operate the train including current speed;
  2. Determine continuously the target speed and limit of movement authority;
  3. Prevent train operation in excess of the target speed or limit of movement authority;
  4. Provide audible and visual warning if the train speed exceeds the target speed or the maximum safe speed;
  5. Enable train doors when the train is docked, enabling only the doors on the platform side of the train; and
  6. Prevent the train from starting if train doors, or the platform screen doors where provided, are not detected closed.

Kavach : Automatic Train Protection System 

Kavach is an automatic train protection (ATP) system indigenously developed by Indian Railways through Research Designs & Standards Organisation (RDSO).

It is India’s very own automatic protection system in development since 2012, under the name Train Collision Avoidance System (TCAS), which got rechristened to Kavach or ‘armour’.

Simply put, it is a set of electronic devices and Radio Frequency Identification devices installed in locomotives, in the signalling system as well the tracks, that talk to each other using ultra high radio frequencies to control the brakes of trains and also alert drivers, all based on the logic programmed into them. One of its features is that by continuously refreshing the movement information of a train, it is able to send out triggers when a loco pilot jumps signal, called Signal Passed at Danger (SPAD), a grave offence in railway operations with respect to safety, and the key to accidents like collision. The devices also continuously relay the signals ahead to the locomotive, making it useful for loco pilots in low visibility, especially during dense fog.


The development of India’s own automatic protection system or collision avoidance system began in 2012. The project was titled as Train Collision Avoidance System (TCAS). The Kavach system is developed as part of the Indian Railways goal to achieve zero accident. The first field trials were carried out in 2016 and with this feedback, initial specifications of Kavach was formulated by March 2017. The Kavach was subjected to tests by an independent third party assessor in the subsequent years. The Kavach system is a safety integrity level 4 (SIL-4) certified technology. Once implemented, Kavach will be the world’s cheapest automatic train collision protection system, costing 50 lakh rupees per kilometre to operate compared to about two crore rupees worldwide.


The system consists of a set of electronic devices and radio frequency identification devices installed in locomotives, tracks, railway signalling system and every stations at 1 km distance. The system currently communicates with its components via ultra high radio frequencies while development of 4G LTE based system is underway. Kavach alerts when a loco pilot jumps signal (Signal Passed at Danger -SPAD), which is the main cause for train collisions. The system can alert the loco pilot and take control of the brakes and bring train movement to a halt automatically when it notices another train on the same line within a prescribed distance. The device continuously monitor train movement and send signals ahead to the locomotives, which is helpful during adverse weather conditions such as fog. The Kavach incorporates key characteristics of European Train Control System and Indian Anti-collision device.

TCAS or Kavach includes the key elements from already existing, and tried and tested systems like the European Train Protection and Warning System, and the indigenous Anti Collison Device. It will also carry features of the high-tech European Train Control System Level-2 in future. The current form of Kavach adheres to the highest level of safety and reliability standard called Safety Integrity Level 4. In the new avatar, India wants to position Kavach as an exportable system, a cheaper alternative to the European systems in vogue across the world. While now Kavach uses Ultra High Frequency, work is on to make it compatible with 4G Long Term Evolution (LTE) technology and make the product for global markets. 

Work is on to make the system such that it can be compatible with other already installed systems globally. The Research Designs and Standards Organisation (RDSO) in Lucknow along with private vendors are developing the system. India wants more private players to take up the development and subseauent production. Once rolled out, it may be world’s cheapest Automatic Train Protection System with the cost of rollout pegged at around Rs 30 lakh to 50 lakh per kilometer, a fourth of the cost of equivalent systems globally. In the next phase, the Kavach system will also be able to recalibrate as per temporary speed restrictions en route, something the system does not yet have.


The Kavach is already implemented on 65 locomotives, 1445 km route and 134 stations in South Central Railway zone, while implementation on 1200 km is underway. The Kavach automatic protection system will be upgraded to handle 160 kmph top speed before it will be implemented on 3000 km route of New Delhi–Mumbai main line and Howrah–Delhi main line as part of Mission Raftar project of the Indian Railway. The Union budget of India for the FY 2022-23 allocated fund for speedy implementation of Kavach system on 2000 km track, and sanctioned implementation on 34,000 km track of Golden Quadrilateral rail route. Newly built WAG-9HH will be equipped with Kavach automatic protection system, these locomotives are designed for a top speed of 120 kmph.


An Automatic Train Examine System –ATES can thus be summarized as a wayside rolling stock health monitor to improve safety in train operations with higher reliability and cost efficiency.

The various features of an ATE System 

  • It measures the temperature of the bearing boxes and rotating wheels.
  • Counts the number of axles in the rake.
  • Measures the instantaneous speed of each wheel.
  • Captures the video of under gear to observe any hanging parts.
  • Collects and analyzes raw data at site and the report all processed site data to an Cloud Notification System (CNS).
  • Report Significant defects and alarms to CNS.

Cloud Notification System (CNS):

  1. System data transferred and analyst with cloud notification
  2. Immediate alerts, for crisis situation
  3. Real time monitoring and visualization of records

It would also be imperative to note that modern technologies provide solutions to combine the latest in sensors and monitoring technologies with customized software and wireless communications to quickly and accurately capture the data needed to maintain and construct rail infrastructure or to manage rail transport assets. Examination of a passenger train can be divided into areas of brake systems, traction systems, suspension systems, structural systems and the overboard systems. The detail above is an attempt to suggest means to visualise these different systems of a passenger coach by use of suitable sensors and analysis through use of Machine learning/ Artificial Intelligence. Accordingly the pre maintenance detection systems have been classified into areas of wheel, Brake, Bogie, Air hose, Coupler, Undercarriage and full train defects detection system.

The modern coaching depot should therefore be equipped with various infrastructure like complete automated train examination system consisting of acoustic bearing detector, hot axle wheel detector, wheel condition monitoring devices including laser wheel profile measurement tool, brake block condition monitoring system, hanging part detector, train view inspection system, fully automated computerised single car test rig, under gear surveillance through AI and other digital tools.

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