The movie is at least 10 years old.
It starts with a man falling off the roof and he survives, miraculously. We learn that the events leading up to this that he played in a casino, with incredible luck. The maffia decided to take him out and drop him from the roof.
So he is infinitely lucky.
He spends a lot of time with a kid, building model train. I don't remember how this is related but the next I remember that this luck is transferable. It is transferred to a young lady. We follow her through various adventures. She needs to get a lot of money (I forgot the reason why.) Among other things, she buys a lottery ticket but when she learns that the drawing is several days in the future, she drops it, even so she knows that it would be the jackpot (because she knows that in very chance she wins.) Passerby picks it up, and immediately hit by a car (so the passerby is not that lucky.)
Eventually she ends up in a casino, where after learning the rules of rulette she makes the money she needs, starting with very little but winning at each spinning.
Eventually she transfers (loses) her luck but I don't remember why and how.