Hi I can hlep you out with Train questions as I've been to londond before:
It run all the time usually a train 1 to 2 mins in between. It busy on the underground so take Water!
I think there a train to Cahlk Farm on the weekend (although i read there wasn't) but not %100 sure. You best buy a Visitor top-up Oyster Card You can use these on buses and train and on DLR (which i'm using) it work like a phone top up you buy the Oyster Card at
It run all the time usually a train 1 to 2 mins in between. It busy on the underground so take Water!
I think there a train to Cahlk Farm on the weekend (although i read there wasn't) but not %100 sure. You best buy a Visitor top-up Oyster Card You can use these on buses and train and on DLR (which i'm using) it work like a phone top up you buy the Oyster Card at