A typical vehicle control system comprises microprocessor based vehicle control unit, associated sensors, distribution boxes, contactors, and display unit with keypad. Based on the application, the hardware and configuration of the system varies.

Medha’s vehicle control systems are high performance microprocessor based modular systems that provide complete traction and propulsion control of the vehicle with continuous monitoring and extensive fault diagnostics. Major functions include Engine control, Excitation control, Propulsion control, Wheel slip control, Auxiliary controls, Protections, Fault Diagnostics, Data recording and Parameter display.

Newer generation Diesel / Electric locomotives, EMUs, DMUs and Metro cars equipped with AC Traction Motors require sophisticated Traction Converters to control these motors as part of propulsion system.

Diesel locomotive and DMU propulsion system architectures provide rectified alternator output as stable DC link bus voltage input to the Traction Converter. Traction Converter could be a combination of one or more inverters each controlling one or more traction motors.

EMU and Electric locomotive propulsion system architectures typically provide secondary winding of traction transformer as input feed to the Traction Converter. Traction Converter would have multiple line converters which convert single phase AC input to a stable DC link bus voltage. A combination of one or more inverters converts this DC bus voltage to 3-phase power controlling one or more traction motors each. For Metro cars, depending on OHE voltage or third rail DC voltage, traction converter may include line converters and inverters or only inverters. 

Medha and Traktionssysteme, Austria entered into a Joint Venture agreement (Medha Traction Equipment Pvt. Ltd.) to design and manufacture 3 phase AC Traction Motors and Traction Alternators in India.

Medha Traction Equipment Pvt. Ltd. produces AC Traction motors which complement Medha's existing and growing portfolio of traction and propulsion products.

Implemented designs for applications including diesel and electric locomotives, DMU, EMU, Metro, High Speed, Tram and Trolley bus

Recently designed motors for 1600 HP DMU, 1.3 MW EMU, and 4500 HP diesel locomotive

Medha offers a wide range of auxiliary converters that are used for powering auxiliary loads in Diesel / Electric Locomotives, EMUs, DMUs and Metros. Typical loads involved are a combination of blowers, pumps, compressors, lighting, fans, air-conditioning (HVAC), battery charging and auxiliary power required by other sub-systems.

Current product offering has a wide selection of input power type such as AC power from auxiliary winding of traction transformer, DC power from Alternators (rectified) / Traction Converter or battery banks. Offered converters are available for range of power rating from 2.5 kVA up to 300 kVA with combination of AC and DC outputs for different loads.

Electronic Governor is a maintenance free alternative to the mechanical Governors popularly used for this application. The Governor consists of a Control Unit mounted in the Driver cab, and an Actuator Unit mounted on the Engine. The Actuator Unit can be mounted exactly on the same Engine base as mechanical Governors. The Governor controls the engine speed, based on throttle handle position (popularly known as notch) selected by the Driver on the Driver Desk. Engine RPM is measured from a Tachogenerator or speed sensor mounted on the Engine. Digital PID control is used to calculate desired fuel rack position dynamically, based on the selected notch on throttle handle and measured Engine RPM. A Stepper motor drive is used in the Actuator Unit to control the fuel rack of Diesel Engine. The Governor also controls load on the engine electrically, to limit horsepower at each notch to a pre-set level, through an electrical interface with the excitation system of Locomotive. Booster (Turbo) air pressure is measured through a pressure sensor mounted in the air manifold. Movement of fuel rack is limited as a function of this pressure to prevent incomplete combustion of fuel, black smoke, excessive engine temperature, fuel wastage etc caused by lack of air to burn the fuel. Lube oil pressure is continuously monitored and Engine is shutdown if the lube oil pressure is less than the specified pressure at each notch position. This protects the Engine from damage due to malfunction of lube oil pump etc.

Vigilance Control Device (VCD) is a microcontroller based safety device which will automatically apply penalty brakes in case the driver is incapacitated. Similar operation is available in older locomotives in the form of Deadman’s Lever.

Operating Principle

Installed on locomotive, VCD gives cyclic warning to the driver. Based on drivers reaction to this warning (in terms of any of the pre-defined sets of actions to be done by the driver), the system automatically resets the alerting cycle. In case, the driver fails to acknowledge the initial alert signals, a set of additional alert indications are given. Even failing to respond to these additional alert signals also will result in automatic application of penalty brakes.

Medha is one of the leading manufacturers of Speed Recorders for Railway applications. These recorders are used on Locomotives and are similar in function to Black boxes in aeroplanes. Speed Recorders are used for monitoring the performance of Loco Driver and especially in the event of an accident the recorded data becomes vital for establishing the cause of accident.

Medha supplies driver consoles in ready to install condition with TFT LCD displays, master controller, brake controller, electrical switches, gauges, lamp indications and other required components and sub-assemblies. Modular panels are used for easy changes/modifications including provisions for future additions.

Driver's display console for Locomotives / EMUs / Metro Cars for showing running data (status information), historical data (Event / Fault logs), maintenance related data and for data entry.

Medha supplies PA/PIS system and LED display boards for trains and coaches Audio system is designed so that the passengers receive relevant information at appropriate times LED displays are customized using different LED sizes, spacing between LEDs, colors (multi/mono), matrix size, mounting requirements etc. LCD display boards are also available as per customers requirements and specifications.

Vehicle remote monitoring solution is an Internet based system connecting all locomotives in the field with centralized Locomotive Management System through CDMA and / or GSM network communication. This solution consists of:

Railways world-over can increase throughput by running longer freight trains which require more motive power. More locomotives when bunched together cause unacceptably high coupler forces. This situation can be overcome by distributing locomotives throughout the consist of the train, which will require a means of synchronizing actions on all locomotives based on driver inputs in the lead locomotive.

Medha's Distributed Power Control (DPC) system, when installed can provide real-time communication between lead and remote locomotives through wireless data radio to synchronize all locomotives in the train. Additional benefits are achieved by applying brakes simultaneously from all locomotives, reducing the braking distances.

Medha offers HEP units from 300kVA-500kVA and higher (1000kVA – 2x500kVA), utilizing capacities of alternator / transformer to meet auxiliary power requirements such as lighting, fans, HVAC, heating, battery charging etc. of complete train. HEPs are IGBT based converters, using sine filters at inverter output to minimize harmonic distortions. Protections for output overload, short circuit and power ground are provided. The converters are designed to suit wide range of inputs.

Both Diesel and Electric locomotives use DC auxiliary power supply and small DC motor used for various applications. These DC machines are failure prone (many times leading to failure of complete locomotive) and hence need more maintenance. To increase the reliability of these motors, Medha has developed 3phase AC motor with inbuilt inverter, so that they can directly replace existing DC motors in use. These replacement motors are compatible with input DC voltage and are within the physical space constraints.

CRDI system includes Engine Control Unit, Fuel Injectors, High Pressure Pumps and various Sensors.

Pump driven by camshaft provides high pressure fuel to all injectors. This pressure level is controlled by ECU depending upon operating speed/power. Each injector has a solenoid valve to accurately control the fuel injection start and duration. ECU controls these parameters based on operating conditions like speed, power, load, Boost Air Pressure, Coolant Temperature etc. This continuous optimization based on various operating conditions is done to reduce fuel consumption and at the same time reduce emissions. In Mechanical fuel injection system, it is not possible to independently control injection start and duration for different operating speeds/powers.

APU is a self-contained system with its own small diesel engine coupled to low capacity compressor and alternator to maintain main reservoir pressure, charge battery, operate driver cabin HVAC system and other small loads as per customer requirement. The main engine is started only when the locomotive is actually required for movement or traction.

The control system on the locomotive continuously monitors the locomotive battery s

Guidance for Optimized Loco Driving (GOLD) system is based on principle that pareto front of different driving strategies for a journey plotted on Journey Time vs Fuel consumed for the journey follows an inverse relationship. Hence, any journey can be completed in different amount of times and there will always be one optimal driving strategy which consumes the least energy (hence fuel) for each journey time.

The system simulates the speed profile for a given trip by taking various factors into account acting on the train. The total available time for a trip is fully utilized to achieve minimum fuel consumption for complete trip. Optimal speed profiles and power (notch) level are continuously displayed to the driver as advisory input.

Medha’s Electronic Interlocking System MEI 633 is a fail-safe, state-of-the-art Distributed Interlocking System. The System has been designed to CENELEC Standards to meet SIL-4 safety specification. It is based on two out of two architecture with a hot standby provision and automatic change-over facility. The System provides all the Interlocking features including Route Setting, Route Release, Point Operation, Track Occupancy Monitoring, Overlap Protection, Crank Handle Operation, Level Crossing Gate Interlocking, and provision for Block working.

Train Control System (TCS) is an advanced and cost efficient SIL4 product ensuring safety of both life and property. TCS is designed to eliminate human error on the part of loco pilot, leading to a catastrophe.

TCS comprises station TCS and Loco TCS.

Medha’s Single Section Axle Counter (SSDAC) overcome track circuit limitations in situations including - water logging or flooding, metal bridges, long block sections, yards with poor wheel shunt lines, high EMI/EMC environments, tunnels, high temperature and sunshine regions, complex and large stations and yards etc.

• 2oo2 architecture 
• Detects 2 or 3 points

Medha's BPAC system ensures that the track section is empty before permitting another train in that section, eliminates human error and controls safe movement of trains between stations. No train is permitted if there is any other train, parted train, detached wheels, rail trolley or other rail vehicle in that section.

Applicable standards include EN50121, EN50126, EN50128, EN50129, EN50159-1 & 2