Started as a bi-weekly service from October 2nd, 1956.
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Was initially running via Old Delhi Junction (DLI) and was diverted through the present route bypassing DLI from June 9th, 1967. In the same year, the service was also made a tri-weekly.
The AC express initially shared rakes with a similar service running between Delhi...
more... and Madras ( started on February 9th, 1957) and switched to sharing rakes with the Bombay bound deluxe express in the 60's.
From 1st April, 1967, similar AC services were introduced between Madras-Howrah and Madras-Bombay. Both these services only ran for a short while and were withdrawn due to lack of patronage. In 1971, the 81/82 tri-weekly service was split into 2 services with 103/104 (present day 2303/04) running via Patna for 2 days a week. (Some details unclear here, possibly 81/82 became a weekly here and 103/104 a bi-weekly). By September 15th, 1971, the Madras bound AC trains were withdrawn and the freed up rakes were used for running the Howrah-Delhi/Amritsar train for 5 days a week. At this time, the 81/82 was running tri-weekly (2 days to NDLS and 1 day to ASR) and the 103/104 was running bi-weekly (1 day to NDLS and 1 day to ASR).
The 81/82, though running on a shorter route, had a slow schedule between ALD-ASN to ensure that it ran in the same slot as the 103/104. In the 1989 budget, the 103/104 was converted from a bi-weekly to a 4-days a week service.
While the Bombay bound AC express was called Paschim express right from the start, the Poorva only got the name some time between 1989-93.