An advisory report is supporting the changes proposed by Network Rail for the most famous feature on the entire Brigg Line route between Sheffield and Cleethorpes.
Network Rail is seeking permission from North Lincolnshire Council to make additions and alterations to one end of Kirton Tunnel.
An application has been submitted requesting listed building consent to install steel security doors on supporting towers, mesh on window and arrow slits, clear debris and undertake general internal and external brickwork repairs.
These works relate to the ornate grade two listed portal at one entrance to the tunnel which was constructed early in Queen Victoria's reign as part of what became the Manchester, Sheffield & Lincolnshire Railway mainline (later renamed The Great Central).
Consulted as part of the planning process, North Lincolnshire Council's conservation officer has raised no objections in a 'summary of advice'.
He has now informed the authority's planning department that the proposed works "are necessary to ensure the long term conservation of the structure and contribute to the health and safety of the public."
He adds: "There is no objection to the mesh on the window openings and the new door as they prevent unauthorised access to the structure, contributing to health and safety and also prevent pigeons getting in which cause damage with their guano. The works are reversible.
"The cleaning and brickwork repairs are necessary to ensure the structure remains in good working order. This will prevent deterioration of the building and maintain its lifespan.
"It is recommended that the application is approved and undertaken as per the submitted plans."
Kirton in Lindsey Town Council has also raised no objections.
North Lincolnshire authority planners have yet to decide the application submitted by Network Rail, which supplied a detailed heritage statement with its application for listed building consent.
This explains the impressive tunnel entrance is in the Gothic style, with imposing cylindrical towers either side.
Completed in 1848, the tunnel is 1,334 yards long.
"The primary reason for the works is to prevent access to the towers, through the installation of doors and window mesh. Minor repair and maintenance works are also to be undertaken," Network Rail explained.
Author and railway historian, Stephen Gay, wrote an excellent picture-packed book Through Kirton Tunnel tracing the history of the line from Sheffield to Grimsby and Cleethorpes via Brigg and Barnetby.
Stephen, a lecturer on railway history, said how pleased the line's engineers were with the end result of this lengthy project.
All the contract workers were supplied with a quantity of ale and a slap-up supper as a thank-you gesture for a job well done.
Saturdays-only passenger trains along the Brigg Line via Kirton Tunnel remain suspended by operating company Northern due to Covid-related staff issues, with a review of the the situation being expected in December. However, freight trains continue to use the Brigg Line.
Picture credit: Stephen Gay.