Madras Time was a time zone established in 1802 by John Goldingham, the first official astronomer of the British East India Company in India when he determined the longitude of Madras as 5 hours, 21 minutes and 14 seconds ahead of Greenwich Mean Time. It has been described as 9 minutes from UTC+5:30 and 33 minutes and 20 seconds behind Calcutta time which puts it at (UTC+5:21). Before India's independence, it was the closest precursor to Indian Standard Time which is derived from the location of the observatory at 82.5°E longitude in Shankargarh Allahabad in Uttar Pradesh.
After Bombay time and Calcutta time were set up as the two official time zones of British India in 1884, railway companies in India began to use Madras time as an intermediate time zone between the two zones. This led to Madras time also being known as "Railway time of India".
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