Primary Maintainance has a schedule.
• Trains running ≤ 3500 kms or ≤ 96 hrs. round trip need to get a Brake Power Certificate (BPC) from its Primary End (PE) only ,
💠 For example, rake of 12988 Ajmer to SDAH needs to get a BPC from Ajmer/NWR (PE) as round trip distance of "Ajmer to SDAH + SDAH to Ajmer is less than 3500 kms. And the same BPC will be valid for return journey 12987 SDAH to Ajmer. If the rake arrives Sealdah on time, it will be taken to...
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Sealdah yard, but will not be given pitline attention. It will be kept in stabling line for cleaning & watering. If 12988 Ajmer SDAH arrives SDAH at 21:00, 12987 SDAH Ajmer may be returned directly from platform at 22:55 with just cleaning & watering. No need of rescheduling. I have seen trains like Kamrup Exp & Chambal Exp were running very late & getting platform returned as up train from Howrah.
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• Trains running more than 3500 kms round trip need to get a BPC from both Primary End (PE) & Secondary end (SE).
💠 For example, rake of 12495 Bikaner to Kolkata needs to get BPC from Bikaner/NWR. Again after arriving Kolkata, the rake will need fresh BPC from KOAA before starting as 12496 Kolkata to Bikaner. It will need to go to pitline, undergear examination is also needed at Secondary End (SE) KOAA yard. As round trip distance from BKN to KOAA & back is more than 3500 kms., so KOAA will again issue fresh BPC
For this reason, u will find if 12495 arrives KOAA just 2-3 hrs late, 12495 gets rescheduled. Same applies for BVC-ASN Exp & GIMB HWH Exp.
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•For intercity trains, Agnibina group has a RSA. Please see from RSA pattern. One complete cycle of the RSA pattern is covered within 96 Hrs. by running 2500 kms (approx). So the rake goes to yard after every 4 days journey. U will find if 53048 somehow arrives 2-3 hrs late at HWH, 12341 will surely get rescheduled by 2-3 hrs., Bcoz the PM is necessary & it takes about 8 Hrs. for this train.
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•For Black Diamond Exp, the train shall get Primary Maintainance, a fresh BPC after every 4 days. Undergear examination is done both at DHN/ECR & HWH/ER. Same for rake of Coalfield Express, undergear Exam is done at HWH/ER (on PM day) and other days at DHN/ECR. So a major part of the examination is shared between the two yards. This was being followed for many years, I hope it is continuing now also.