How big is your 5 yo? We used a Joovy Caboose for my 4 yo (who was pushing the 45 lb limit for the jump seat) and my 33 lb 2 yo last spring. It worked pretty well, although it doesn't fold as easily as an umbrella stroller. We were able to get it on the trains without much trouble.
Jennifer
Mommy to a big girl and a little girl with a sweet boy in the middle (and always missing our sweet baby boy #2, stillborn 7/12)
"The work of today is the history of tomorrow and we are its makers." Juliette Gordon Low