There are 381 stations, 278 miles, 11 lines – and 12 hours.
Simon Boulton’s London Underground challenge is going to involve military planning.
He and fellow Bridlington Lions Club member Chris Beesting are aiming to pass through every Tube station in the capital in half-a-day.
“I have sat down for more than 10 hours looking at the London Underground map, splitting it up into squares, and thinking about which will be the best route,” admitted Simon.
“We’ve got rush hours to deal with and we have to overcome any unplanned delays, which might mean getting a bus to another station if the line is closed.
“You can’t really train for it but you have got to pace yourself.
“This is a fantastic challenge. I’m really looking forward to it.
“Chris is going to take photographs of all the stations if he can and after we have done it, we are hoping to put on an evening at North Bridlington Library talking about it
The duo will start at Heathrow Terminal Four at 7am on Tuesday, September 12 and hope to have ticked off all 381 stations by the time they get back there at 7pm that evening.
Even the date of the challenge has been chosen carefully, because Tuesdays are likely to be quieter than weekends or the start and end of the working week.
And September misses the crowds of tourists during the summer holidays.
They will carry rucksacks with food and drink so they don’t have to waste valuable time stopping to buy meals and snacks.
Simon’s love of the underground comes from his time working in the capital.
“I used to work in London as a concierge at the Hilton International Hotel and I met people who tried to do record attempts on the underground,” he said.
“We are not trying to break a record, this is purely to raise as much money as we can for good causes in Bridlington.
“I love the London Underground. I have always been intersted in how it operates and I even got to ride in the cab of a train to Heathrow.
“London has a superb underground system, the best in the world.”
Internationally, the Lions are celebrating their centenary and each branch has been asked to come up with a fund-raising challenge.
“This will be the biggest challenge that Bridlington Lions Club will do for our centenary and we are going all out,” said Simon.
Members will have sposnor forms soon, or donations can be made at the Lions Club book shop in Prospect Arcade.