Lewis Wing, who lives in east London, grew up near a Tube station and became a passionate fan from the age of just three.
Now six, he has just completed a tour of all the stations in London – all 272 of them – and hopes to have broken a world record as the youngest person to complete the mission.
The Tube-loving schoolboy began his project with the help of mum Sheina Vasudevan, 46, and dad Peter Wing, 49, three years ago.
He visited the final two stations on his list on September 20 - Battersea Power station and Nine Elms – and is now waiting to hear from whether he has broken the record.
Sheina said: “We live near the Jubilee line depot so we can only assume his love blossomed from there.
“We were taking him on the Tube as transport from three months, and as soon as he could speak he was asking to go on the Tube.”
Tube-mad Lewis added: “I like all trains. They’re awesome.”
The schoolboy first began his mission to visit all 272 stations in London aged three when he and his parents would catch the Tube to travel around.
He became more and more interested and began requesting visits, as well as doing his own research, and even memorising the Tube map - which he can recite any route from by heart.
Sheina began decorating her son’s bedroom with a variety of London Underground-themed decorations - from bedsheets and cushions to a hand-decorated clock - and his love only grew from there.
They decided to take a snap of Lewis at every station they visited - and it soon spiralled into a challenge for him to visit every station in London.
Lewis ticked off the final two stations on his list - around three years after beginning his mission - on September 20.
Sheina said: “We went to Nine Elms and Battersea Power Station on the day they opened.
“We had to contact Transport for London to find out when they would actually be open to go and complete the set.”
Lewis added: “We went straight from school - it was the most tiring Monday of my life.”
Reflecting on the past three years, he said his favourite stations were Sudbury Town “because it looks nice on the outside” and Stratford “because it looks nice on the inside”.
Now he has completed his mission, the six-year-old is waiting to hear back from Guinness World Records on whether he has become the youngest person ever to visit all 272 stations.
Sheina said: “He knows everything about it - we don’t even question his knowledge any more. Every morning he checks the Transport for London status report and it shows.
“Lots of six-year-olds sit around in front of the TV or a games console all day - so it’s an interesting passion to have!”
She added: “Now Lewis has made it his mission to visit every national railway station - there are more than 2000.
“I think he can do that one for himself when he’s a bit older!”