CMRL begins overhauling of trainsets

CHENNAI: To ensure the safety and reliability of Metro Trains, Chennai Metro Rail Ltd (CMRL) has begun intermediate overhauling (IOH) of trains as per the requirements of Original Equipment Manufacturer (OEM) maintenance manuals after six years of train operation.

An official release from the CMRL said Metro managing director Pradeep Yadav along with other senior officials inspected the first overhauled Metro Train set from CMRL Rolling Stock Maintenance Facility at Koyambedu.

It said that the work involves removing the bogies (undercarriage with four or six wheels pivoted beneath the end of a Metro Train Vehicle) from the car body and stripping out of bogie components. “Inspection of welding joints, welding and repainting of bogie frames are then done. Primary suspension springs are 100 per cent replaced. The wheels are re-profiled for passenger comfort. The axles are then subjected to ultrasonic flaw testing to ensure that no internal defects exist. Other worn-out components are replaced during this process,” it said.

A complete overhaul of traction converters, auxiliary converters, brakes systems and air conditioning systems are also performed, it said, adding that in addition, deep cleaning of air conditioner ducts, train exterior and the interior is also performed using special environment-friendly chemicals.

After overhauling, it said that the train undergoes static tests and all functionalities are restored. “Then dynamic tests are also carried out in test track up to 40 kmph and in mainline up to 80 kmph. The Metro train is then certified fit for passenger service by Competent Authority,” it said.

The release said that the Metro Trainset No 15 is the first trainset to be overhauled by CMRL‘s in-house team in coordination with maintenance staff. “The cost of overhauling of one trainset is around Rs 1.77 crore and the time taken for completion of the entire process is 40 days,” it added.