Maintenance Schedules

Last updated on July 10th, 2013 at 10:24 am

Schedule of Inspections and overhauls for rolling stock and fixed infrastructure is fixed by RDSO. For electrical department, the rolling stocks are Coaches, EMUs, Locomotive Coaching and Freight, Tower Wagon and fixed infrastructure are 25kV Overhead Equipment and its power supply equipment, General Services (standards not fixed by RDSO) etc.

Schedule Inspection

Activity of Schedule inspection involves monitoring the condition of equipment through

• Instrumentation
• Railway staff physically using his senses.

Objective

• To replace all those parts which can’t last from overhaul to overhaul depending upon the service/duty cycle such as lubrication, brake blocks, tap changer oil etc.
• Cleaning and checking why dust finding entry into the asset. Is it natural or abnormal?
• Inspect for any uneven wear sign, rubbing, overheating, sign of smoke, accumulation of oily or moist dust – an indicator of oil or air leakage respectively, sign of bolt loosening, deformation/displacement, breakage, external hitting on under-gear and roof items, missing fasteners etc.
• Condition monitoring for air leakage from any of the equipment by external supply of air or during pre or post-testing.

Experience sharing

• A defect noticed during schedule inspection is a warning of the fact that the asset was working on the line with this defect and is unavoidable failure.
• There is a general myth that loosening of the bolt is natural due to vibration and should be tightened. No bolt should get loosened unless there is a defect. Identify the defect
• Ensure satisfactory working of protection system.
• Don’t use GI wire for securing, leaving fasteners or any other item inside the equipment after the maintenance.
• Avoid over lubrication as dust will accumulate around it.
• Prohibit use of adhesive tapes around electrical joint/connection

Objective of Overhauls

• Overhaul is an activity in which the equipment is opened, each part cleaned and examined, must change items taken out and replaced with new kit, assembly and testing to confirm the functional test, transportation to locomotive/coach and fitment.
• Make a note of any uneven sign on any component  during overhaul for statistical analysis at a later date
• Must change kit is actually replaced, released kit taken back and examined for the in-service functioning of the components  and decision taken for value engineering, particularly for high value components of the kit
• Overhauled items shall move from section to the rolling asset as loco/coach set in a designed trolley and “handle with care”.
• Keep a record of the overhaul item in all respects

Experience Sharing

• The must change kit established over the period is supplier specific and of the items which are either wearing or affected due to working in air environment.
• There are many other items, particularly low value items, which are changed on condition basis. Local units shall identify and form such repair kit as must change items. The items involved are: switches, lamps, interlocks, grommet, flexible conduits, pins and bushes, etc.
• Loco Pilot seat, latches, linoleum floor sheet, body gaskets shall be replaced as must change item depending on expected life on a specific class of locomotive.
• The equipment taking more time for overhaul shall undergo technological up gradation. Condition Monitoring is a better option to defer opening of such equipment at a shorter interval.
• Level of stripping shall be established, particularly electrical/electronic items. With such equipment, replacement of gaskets, switches, higher duty cycle interlocks shall be a must change an item.
• Is it necessary to remove pressure gauzes, meters, relays just for checking the set value? Is rolling stock where it works itself is not a good test bench for the purpose. Frequent removal/handling of items does disturb the base which generally is a maintenance free item

 Do’s During Overhaul

• Overhaul items shall be transported from the section to locomotive/coach/emu in unit set in specially designed trolley to avoid damage during transportation.
• Functioning of equipment shall be tested by giving external air and control supply on rolling asset. This provides an environment of low noise and when all the high voltage equipment is approachable. This provides a more conducive environment for functional test of all equipment such as brake valves, roof, pantograph, horn, wiper, sanders, BA panel, GR etc.
• The advantage is that if tested with pantograph raised condition, not only defect identification is difficult but also there is tendency for temporary repair.
• Identify areas of temporary maintenance being done and term it as bad maintenance. It is like a virus and never be confident that it is completely eliminated.

Don’t During Overhaul

• Don’t permit use of GI wire for securing wires, pipe etc. as it is likely to break due to fatigue or may touch some conducting body inadvertently.
• Don’t use any external sealing compound over and above the sealing gaskets for external precaution as the condition of original gasket will never be known which may deteriorate and develop cracks/permanent set thus compounding the problem
• Never leave any foreign body inside the locomotive such as waste cotton, fasteners, nuts, washers inside the locomotive.

Periodicity of Schedules

There is no thumb rule to decide the periodicity. However factors responsible for improving periodicity during the last 30 years had been

• Introduction of roller suspension bearing with Hitachi make TM and TAOCHI.
• Increasing the oil sump capacity of  the compressor
• Introduction of metalized carbon strips on pantograph
• Introduction of kit system during overhaul and condition monitoring techniques.
• Differentiating maintenance need of a coaching and freight locos.

The basic factors responsible for change of schedules had been

• Lubrication
• Life of the wearing components
• Identification of Duty cycle

For increasing periodicity, dependency on these items by improving designs/redundancy shall reduce