a little help please from those savvy in the london transit scene, please:

how difficult is it to hail a taxi at the national gallery at 5:30pm on a weekday?

what would the be the subsequent commute time to the tower of london?

how difficult is it to hail a taxi at the tower bridge (south end) at 6:45pm on a weekday?

what would be the subsequent commute time to waterloo international?

do london taxis take u.s. credit cards (magnetic strip)?

how many trips on the tube would it take to make a one day zone 1-2 travelcard the better option?

can individual tube trips be purchased with a u.s. credit card?

thanks in advance...bdj

I shouldn't think you'd have to wait long for a taxi at those times and locations, but I'm no expert. Likewise I can't see why they wouldn't accept old-fashioned credit cards, but I don't know.

At that time of day, the Tower would be closing about the time you got there. For either of those trips I'd allow about 20 minutes.

Single tube fares are designed to be prohibitively expensive: £4 a pop if you're paying singly. No point getting Oyster to pay as you go for just a couple of trips, so get a one-day travelcard. I would suggest buses as a cheaper option except that it sounds as though you're trying to avoid changing money into sterling for small sums. Bus 15 from Trafalgar Square to the Tower and RV1 from Tower Bridge to Waterloo would in any case be more direct options than the tube, though slower than a taxi (and at 5.30, the 15 is likely to be crowded).

Not all taxis take credit cards. I've no idea how long you're likely to add to your journey by rejecting those that don't. At 1730 and 1845 on a weekday, how long you wait for a taxi depends on the weather: if it's raining, maybe up to half an hour.

And probably longer at the south side of Tower Bridge: no-one drops there, especially after work.

As far as I'm aware, every tube station has a machine that takes credit cards, and none require a PIN. But the credit card-enabled machines seem to break down surprisingly often, and obviously none of us have old-fashioned credit cards anyway.

You might want to repost, with a title specifically seeking people who've used old-fashoined cards on the system.

Maybe I can help a little - my office in right next door to the Tower of London and I have a major clinet in The Strand so I make the trip regularly.

Firstly check out http://www.tfl.gov.uk/ this is the official London transport site and will tell you all you need to know re fares routes etc. Just pug in start and destination and it will provide pretty much all you need.
Quckest way from the National Gallery to the Tower is by tube from Embankment station to Tower Hill on teh District or Circle lines. Embankment is just behing Charing Cross Station accessed via Villiers St.

Most scenic way is by bus or taxi (around £7) along the embankment (you will pass the London Eye, Shell Building, OXO Tower and will have a view of Tower Bridge.

Specific answers to your questions.

It should be fine getting a taxi at 5.30 (unless it is raining in which case it will be nigh on impossible!

Time to tower - 10 mins by tube (+ 5 at either end from stations

Taxi at Tower Bridge - you will probably have a bit of a wait at that time + south of the river is always more difficult! There is also the Waterloo and City tube line which runs from Monument Tube to Waterloo non stop in 10 mins.

Some, not all, taxis do take Credit cards but ask before you get in - some cabbie won't take cc for small fare or have a minimum or make an additional charge (£5?)

How many trips with a one day travel card - Single trips cost £1.50 on Oyster so you would need to make 5 trips for the Travel card to be better value.

Individual trips can be purchased at staion with a US cc but you do need a PIN to get one from the machines. I would imagine that the ticket windows would accept a non PIN card if you don't mind queuing.

Have fun!

if i'm going to be in london for a day and plan on taking two trips on the tube, maybe three - would that still favor a one day zone 1-2 travel card over oyster or single tube fares?

thanks in advance...bdj

For price and convenience a one day travel card seems to make the most sense for your day. I believe you still have to put a "deposit" of 3 pounds on an Oyster card. If you do I believe you can get it back by turning in your Oyster card at the end of your day. That seems like a lot of trouble for one day. If you were going to be back in London from time to time or know someone else who will you could get an Oyster card and use it again another time.

A one-day travelcard for zones 1-2 is £5.10 off peak (after 0930 Mondays to Fridays, all day at weekends) or £6.60 including peak times. The travelcard is valid on trains, tubes and buses, and gives a 33% discount on most boat trips.
A single tube journey, even for one stop, is £4. So, even for a couple of tube journeys, a travelcard is cheaper.

Just wanted to add that I recently (in June) used my North American credit card in the machine in a tube station to buy the one day travel card. I don't have a pin and my card has a magnetic strip, not a chip - it wasn't a problem!

outstanding responses...thanks.

must the off-peak travel card be purchased after 09:30 or can one buy it in advance for use after 09:30?

much obliged...bdj

You can buy your off peak travel card any time - just can't use it until 09:30

Just one comment about a taxi at Tower Bridge -- IF you end up wanting a taxi there is a big hotel (the Tower Hotel - duh )just at the north end of the bridge. If you are having trouble hailing a cab, walk to the hotel - cabs come and go regularly dropping guests off.