Todor Karzhev, aged 44, of Stirling Road in Clapham, London, was jailed for 38 months after changing his plea on the day of sentence.
Sheffield Crown Court heard Karzhev was rumbled by a Network Rail employee who was carrying out routine fire safety checks at premises under the railway arches on Sussex Street on February 2017.
The court heard the employee alerted British Transport Police after approaching the rented premises noticing a 'strong smell of cannabis'.
Officers forced their way in through a fire escape and discovered a well-established cannabis factory with two large Portacabins housing nearly 300 mature plants and an irrigation system with water tanks.
A full search of the premises led officers to discover nearly eight kilos of cannabis with a street value of more than £76,000.
The court heard numerous CCTV cameras were set up around the building which were connected to a broadband router streaming live images - watched by Karzhev himself.
As the premises were being searched, Karzhev rang Network Rail asking why people were in his rented building, having seen the discovery on streamed CCTV.
When interviewed, Karzhev claimed he had sub-rented the property and was unaware of the cannabis factory.
But when detectives later searched Karzhev’s home address in London, they seized phone and car Sat Nav records which when analysed, placed him at the premises in Sheffield on numerous occasions.
Investigating officer DC Ian Grice said; “Despite Karzhev’s best efforts to run a cannabis factory from under Sheffield station, a safety check uncovered his illicit operation and he had now been landed him with a lengthy jail term.”