you can take it on the tube anytime, whether you'll fit onto a train is entirely another matter. I tend to only bring mine on the tube early mornings before the main rush when i know i'll get a seat in the luggage area with the fold down seats.
as for tips on wheeling it. you can unfold just the handlebars and use it kind of like a wheeled suitcase arrangement.
you can take it on the tube anytime, whether you'll fit onto a train is entirely another matter. I tend to only bring mine on the tube early mornings before the main rush when i know i'll get a seat in the luggage area with the fold down seats.
as for tips on wheeling it. you can unfold just the handlebars and use it kind of like a wheeled suitcase arrangement.