Purulia Express: লালপাহাড়ীর দ‍্যাশে যাবি? চিন্তা কিসের লো? বিকাল বেলা হাওড়া থেকে পুরুল্যা এক্সপেরেস পাবি। - Dip

@kya_karun: Re# 148326-0
POH

Each coach which carries passengers on Indian Railways undergoes what is termed as Periodic Overhaul (POH) every 12 months. You can find at the back of each coach the date markings of the date when POH was done, and the scheduled date of return for the next overhaul.
Technically,...
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this should be 12 months. But a lot of coaches are actually marked for 18 months. Some are marked 12, but it is common to find coaches which have exceeded that. This means that instead of every 12 months, a coach undergoes overhaul every 15-18 months.
In a POH, the broken parts are repaired, light bulbs/tubes replaced, torn seats replaced, suspension overhauled, batteries replaced, wiring repaired if needed, additional charging plug points provided and the coach is repainted.