Two reindeer were daubed on a wall “pulling” a bench on Vyse Street beside Birmingham’s Jewellery Quarter station.
On Monday Banksy posted on Instagram a touching video of the artwork highlighting the plight of Britain’s homeless at Christmas.
Crowds are flocking to the spot to see the artwork, to which one local person has added a red nose.
Moved by Banksy’s message, Network Rail today took the unusual step of protecting a piece of graffiti on its property.
Local maintenance engineer Chris Edwards drilled Perspex sheeting into the wall to protect the image.
The iconic artwork comes a few weeks before Network Rail and the Midland Langar Seva Society host their annual Christmas Eve meal, at Birmingham New Street station, for local homeless people.
David Golding, interim route managing director for Network Rail's Central route, said: “As a railway family our hearts go out to the homeless, especially at this time of year. Banksy’s wall art has captured their plight so well. It’s right we protect it so everyone can see it.”
David added: “We discourage any graffiti and we spend a lot of time removing it from around the network … but it’s not every day we get a bona fide Banksy.”
Network Rail’s discourages any defacing of its property policy on graffiti is to remove anything obscene.