EMU Maintenance and Overhaul Procedures

A daily inspection carried out by the running section on EMUs. It can be done at the shed or an outstation if convenient.

A scheduled inspection performed on EMUs after a trip, done at the homing shed.

A monthly inspection of EMUs done at the homing shed.

An inspection of EMUs performed quarterly at the homing shed.

An inspection of EMUs performed every 6 months at the homing shed.

A scheduled maintenance on EMUs done at the homing shed.

A major maintenance procedure on EMUs done at the nominated workshop.

A certificate verifying the fitness of EMUs, similar to the fitness certificate for locomotives (locos).

Testing of the air brakes on an EMU train before operation. Performed by a supervisor at both end driving cabs.

Connections between the cars of an EMU train. Important for air brake operation.

Using split pins to keep the joint ring aligned while the cylinder is lifted.

Tighten nuts evenly, opposing nuts together, final tightening during vacuum.

The release valve head is normally closed, cutting off communication. Opening it pulls the lever.

A defective seating or diaphragm washer allows air into the piston when vacuum fails, and the vacuum cylinder won't work properly.

Remove all rubber parts when dismantling, clean with French chalk, use solvent carefully on metal, remove solvent traces before replacing rubbers.

The piston travel should be a maximum of 4 inches (100 mm) for effective brake power.

The Engine Examiner inspects reported issues, checks auxiliaries, feels axle bearing temperature, examines mechanical components.

Visually inspect traction motors for damage, such as flash marks, broken brushes, damaged pigtails, etc.

Ensure auxiliary machines are running quietly and without unusual noises.

Quickly inspect all electro-magnetic contactors and relays for any issues.

Verify the proper functionality of the air-blast circuit breaker.

Clean battery vent holes, check intercell/main connections, record specific gravity & voltage, top-up as needed, & lubricate connections.

Check and fix any faults with lights and fans.

Clean underframe equipment, paying attention to oil accumulation areas, and filters, as needed.

Ensure the correct operation of the RGCP system.

Check the self-lap feature of the EP brakes.

Measure tyre root and flange wear, record data, reprofile tyres if needed, and maintain within permissible diameter limits.

Inspect axle boxes, especially the back dust-guard area, for grease leaks and cracks.

Inspect the reversible gear box of the speedometer.

Check suspension bearing housing bolts for tightness.

Inspect gear-case securing bolts for tightness.

Check the friction damper liners and pads of the motor coach.

Inspect the friction damper spring assembly for proper function.

Measure and verify the compressed height of the swing bolster springs.

Inspect the condition of draw-gear rubber pads for wear and tear.

Disassemble and inspect 'Schaku' couplers, lubricating as required.

Measure and record the heights of the buffers for accurate alignment.

Examine body panels for rust, corrosion, and damage.

Verify the functionality of the passenger alarm device in each coach.

Clean the suction strainers of the auxiliary air compressor.

Inspect all brake cylinders and tighten the foundation nuts.

Check air gaps, spring pressure of auxiliary contacts, and clean insulating surfaces in EP contactors.

Inspect the reverser and changeover switch (WCO).

Clean cooling fins of rectifier trays, air ducts, power connections, capacitors, and HRC fuses.

Open and inspect Master Controllers, wipe insulating surfaces, and check contacts.

Clean supporting insulators and check tightness of transition resistances connections.

Clean traction motor brush-holder insulator and check earth-return brush-gear and junction box connections.

Check the tightness of main compressor foundation bolts.

Inspect air gaps, flexible shunts, knuckle spring pressure, and hinge pins in electromagnetic contactors.

Inspect push button switch contacts and terminal connections.

Check all knife switches.

Check the supply continuity of the current limit relay LT.

Inspect the voltage stabilizer transformer.

Clean the headlight reflector.

Inspect commutator and carbon brushes of all fans. Renew if needed.

Examine axle boxes and change grease if required.

Check pantograph for upward pressure.

Change the oil in the compressor crankcase, change the oil filter and Check oil pressure.

Decarbonize the valve assembly.

Renew crankcase oil for the auxiliary compressor.

To renew worn-out brake blocks, focusing on differential wear between motor coaches and trailers.

Dependent on factors like daily mileage, train types, and brake block quality, determined at the Zonal Railway level.

Visually check bogie frames for cracks or damage.

Inspect axle guide helical springs for breakage.

Check axle guides for excessive oil leakage.

Verify the tightness of axle guide oil filling caps.

Inspect axle suspension bearings, checking oil levels, pressure, and tightness of drain/filler caps.

Check gearbox lubricant level and tighten associated bolts.

Adjust brake pull rods, rigging, and slack adjusters.

Thoroughly inspect brake rigging bushes, pins, split-pins, and cotters.

Check the center pivot for proper functionality.

Inspect 'Schaku' couplers for cracks, deformation, and damage.

Inspect buffers and lubricate buffer plungers.

Lubricate screw couplers.

Check doors, windows, handles, footsteps, safety bars, and handrails.

Check protective screens for look-out glasses for proper security.

Clean driving cab window panes and swab clean cushions.

Inspect pantographs for flash-marks, wear, and cleanliness of insulators.

Lubricate articulation and bearing joints and pans.

Check the crankcase breather pipe of the compressor.

Check oil level in the auxiliary compressor and top up if needed.

Manually operate control magnet valves to check EP contactors and reversers.

Check transformer oil level and top up if required. Check for oil leaks.

Check the color of silica gel and replace if required.

Inspecting all wheels for loose tires, cracks, flats, and other defects, along with bogies and running gear for abnormalities.

Immediately after stabling, manually checking axle boxes for any issues, and examining axle box covers.

Inspecting axle guide helical springs for any breakage or damage.

Checking brake blocks for wear, cracks; renewing badly worn ones; and adjusting slack adjusters to maintain 12 mm clearance between blocks and wheels.

Inspecting brake rigging components (bushes, pins, and others) for damage or breakage.

Visual inspection of bolster helical springs for any issues.

Inspecting and cleaning look-out and headcode glasses.

Checking cushions for damage; replacing badly damaged cushions.

Testing the passenger alarm chain system in at least two coaches of a train.

Visual check of pantographs for any defects

Checking the oil level of air compressors and suspension bearings; topping up if needed.

Testing the automatic drain valve of main reservoirs and draining other reservoirs.

Testing the horns at both ends of the train.

Checking for noticeable air leaks in the compressed air system.

Checking connections for air hoses between train units.

Testing the brake controller at each driving position to ensure correct operation.

Testing the deadman's device in each driving cab.

Testing pantograph raising and lowering push buttons in each driving cab.

Checking the Master Controller in each driving cab.

The pressure in the main reservoir, controlled by pressure governors on each compressor, is maintained between 5.8 and 7.0 kg/cm2.

The pressure in the brake pipe, running the length of the train, is maintained at 4.57 kg/cm2 to keep automatic brakes released.

A unit in each coach that contains control valves for emergency and automatic brakes.

Motor coaches generally have four brake cylinders per bogie, while trailer coaches have two per bogie.

The brake controller has five positions: Release/Run, Full Service EP, Lap (auto-application), Service Automatic, and Emergency.

A relay in each driving cab that controls the brake control train wires based on brake controller operation.

Five train wires (EP supply, application, holding, indication, and return) carry control signals for the air brake system.

Each coach includes an EP brake unit containing combined control valves for both the EP and automatic brake systems.

A pipe-bracket arrangement uses a casting with cored passages to connect brake valves internally, with only main reservoir, brake pipe, brake cylinder, and atmosphere connections externally.

An isolating valve switch operated by the driver's key activates the brake controller in the operative driving cab.

A mechanism that automatically controls the brake cylinder pressure based on the controller handle position, preventing over-application.

The pressure within the brake cylinders, crucial for effective braking, controlled by the EP brake system.

Position of the controller handle determines the level of brake application and therefore the pressure in the brake cylinders.

Electrical wire that energizes holding magnet valves, thus closing the exhaust from brake cylinders, which is important for holding the brakes.

Electrical wire that energizes the application valves, allowing air to flow to the brake cylinders for applying brakes.

A mechanism that regulates brake cylinder pressure by responding to changes in handle position.

A safety valve in the EP brake system that prevents the brake cylinder pressure from exceeding a predetermined maximum.

Brake cylinder pressure achieved while the controller handle is between positions I and II.

Safety valves in compressed air brake systems that prevent overpressure in brake cylinders.

Checking the mounting and support of equipment suspended below.

Mechanism in the brake controller that ensures proper brake application.

Maintaining the pilot valve in the Master Controller by cleaning and greasing.

Adjusting the operating pressure of pneumatic governors for optimal performance.

Checking the condition of cones and rollers in EP contactors, and tensioning knuckling springs, renewing washers, and inspecting shunt connectors.

Checking the condition and operation of the reverser and changeover contactor.

Testing the dielectric strength of transformer oil from conservator, reactor, and transformer tanks, filtering if below 40kV for one minute.

Checking the connections and condition of couplings between vehicles.

Checking insulators and diodes for cracks and correct tightening.

Lubricating the interlocking mechanism and notching cam roller, and checking contact parts.

Checking the pressure of brush springs on traction motors and lubricating armature bearings.

Checking MG Set bearings for leaks and lubricating as needed.

Overhauling and testing EP brake valves and replacing rubber components.

Overhauling the gear box and testing the speedometer.

Checking 'Schaku' couplers for wear and damage, and lubricating as required.

Overhauling the servomotor used in pantograph systems and checking adjustments.

Overhauling and testing pantograph EP valves.

Removing and overhauling main and auxiliary compressors; testing volumetric efficiency.

Overhauling and testing the brake cylinders.

Overhauling the motors of all AC and DC auxiliaries.

Removing and overhauling the air blast circuit breaker testing on a bench.

Checking the settings & operation of all relays manually.

Overhauling all coach fans.

Removing battery set to battery room, checking, and performing two charge/discharge cycles, and capacity test.

The green lamp indicates availability of the electrical power supply for the emergency brakes.

When brakes are applied and pressure increases in all bogies, the orange lamp illuminates.

The pressure switches in all coaches are connected sequentially to detect pressure build-up in all bogies.

Loss of the green lamp signals a complete EP brake failure.

Orange lamp not lighting upon brake application signifies part of the emergency brake system isn't working.

The automatic brake system, controlled by the brake controller, applies brakes to slow or stop trains when needed based on air pressure.

The pressure in the brake pipe is regulated via a reducing valve to a standard value of 4.57kg/cm2.

A vital component in each coach, the triple valve changes the brake pipe's pressure to operate brake cylinders.

When the brake pipe pressure is 4.57 kg/cm2, the triple valve allows brake release.

Stores compressed air in the coaches for quick brake application.

The triple valve limits brake cylinder pressure to a maximum of 3.5 kg/cm2.