Lincoln St Marks Railway Station - Station Street, Lincoln, UK - Wikipedia Entries on Waymarking.com

Wikipedia has an article about the former St Marks railway station that tells us:

St. Mark's railway station, the first in Lincoln, was opened by the Midland Railway in 1846. It was originally a terminus; the line was extended through the station only a few years after it opened, to connect with the Great Northern Railway just to the east of that company's Lincoln Central station. The Durham Ox Junction was also crossed by a road, leading to many delays. The junction was crossed by Pelham Bridge in the mid-1950s. Until its closure St. Marks was the mainline station, with through services from Cleethorpes to London King's Cross. Prior to closure of the Lincoln-to-Grantham line during the Beeching Axe, London services had used Lincoln Central. Direct services from London ceased with rail privatisation; after this, travel to St Marks required a change of train at Newark North Gate.

To avoid unnecessarily operating two stations, St Marks closed in 1985; services were diverted to the nearby Lincoln Central. The construction of a new 80-metre length of track to the west allowed services from Newark Castle station to reach Lincoln Central. The grand ionic portico that was once the entrance has been preserved and, as of January 2007, was home to Lakeland Limited as part of the commercial development of the site. A mock signalbox has also been erected in the car park on which has been affixed an original sign from the station. The remainder of the former station site is now St. Marks Shopping Centre. The redevelopment, in keeping with the preserved buildings, won an Ian Allan Heritage Award in 2009, which is commemorated by a plaque.

As mentioned, the building is Grade II listed with the entry at the Historic England website advising:

Former railway station and adjoining office, now a taxi office. 1846. By WA Nicholson. Gault brick, with stone dressings and hipped slate roofs. 4 ridge and 2 side wall brick stacks with corbels.

Classical revival style. Plinth, blocking course, and renewed brick parapet to main range. Single storey, 17 bays. All openings in the main range are boarded up. North front has a central portico, 3 bays, with paired Ionic columns on iron bases. Beneath it, 3 doorways with pilaster surrounds and cornices, the central one with consoles. beyond, flanking wings, 4 bays, each with 3 windows with cornices and consoles. left wing has an additional opening with brick surround. Right wing has a plain doorway to left. Beyond again, terminal pavilions, 3 bays, each with 3 windows and Doric pilasters.

South side has plain openings and platform projecting westwards beyond the station buildings. At the east end, next to the street, an office building, 2 bays, with a moulded doorcase and 3 windows to the north. Late C20 fenestration towards the street. IA Davies has also been suggested as the architect.