Understanding London's Railways

is there one train line? - no

acquaint yourself with a map of the London Underground https://tfl.gov.uk/maps/track/tube

trains to Watford Junction (for Harry Potter studios at Leavesden) depart from Euston

trains to Oxford depart from Paddington

trains to Cambridge depart from Liverpool Street or Kings Cross

trains to Salisbury (for Stonehenge) depart from Waterloo

use this http://www.nationalrail.co.uk/ to get an idea of train times and prices (you can buy Advance tickets to Cambridge if you want to save money)

London has major train stations all around the town. You will connect to the train you need by taking the Underground or bus to reach the various stations.

When you're planning your trips know the line, the names of some of the cities at the end of the line, the platform the train departs, the number of stops to your destination and the name of the station before your stop. The announcements, even in English-speaking countries are always difficult to understand and it's nice to know that your stop is next, so you can make your way to the doors as the train is approaching the station instead of trying to peer out the windows to see if you're at your stop or not.

You'll want Oyster cards for each traveller that will get you around London and to Watford Junction station for the Harry Potter Studios tour. Google Maps and the tfl website are great resources for planning your journey.

At the end of your stay you can get refunds for your Oyster card £5 deposit and any unused fare at attended Underground stations or one of the Visit London Tourist Centers. If you're leaving from Heathrow airport, take the Underground there and do the refund there as you depart. Leave extra time for this.

I highly recommend taking the bus over the Underground. London double decker buses are not only more comfortable than the tube, but they are also typically less crowded outside of commute time and nothing beats the great view from upstairs. It's super fun for kids of all ages.

Last but not least, I feel like when I was 13 I did a better job of figuring out transit than I do now as an adult. Kids are so fast with learning new things and systems.

For your question about railways, we have an expert here, and I'm sure he will provide answers as soon as he sees your post.

For your trips out of town, consider going with the London Walks Company. They have been in business many years, and have an excellent reputation. They do guided walks around London, which are very reasonably priced, $7 to $15 per person. They also have a ton of group day trips out of London, in which the guide meets you at the train station, all members of the small group board the train, and the guide gives a walking tour at your destination, and goes with you back to London on the train. Their guides are great. I have been on walks in London with them, and trips out of London with them, and enjoyed them all. Stonehenge is a great trip to do with them. They also go to Oxford and Cambridge, and a variety of other places. Have a look at their website, here. www.walks.com

See their Stonehenge/Salisbury trip on this page, also their Oxford trip, and their Cambridge trip:
http://www.walks.com/London_Walks_Home/Day_Trips_from_London/default.aspx
http://www.walks.com/index.aspx?PageId=988
http://www.walks.com/index.aspx?PageId=17#12942
http://www.walks.com/index.aspx?PageId=985

To access main line (above ground) stations using the Tube (Underground) ...

For trains to Leavsden (for Harry Potter studios) departing from Euston
-- Take Victoria Line Tube northbound from Victoria to Euston

For trains to Oxford departing from Paddington
-- Take Circle Line Tube westbound from Victoria to Paddington

For trains to Cambridge departing from Liverpool Street or Kings Cross
-- Take Victoria Line Tube northbound from Victoria to Kings Cross

For trains to Salisbury (for Stonehenge) departing from Waterloo
-- Take Circle or District Line Tube eastbound from Victoria to Westminster and change to Jubilee Line Tube southbound to Waterloo

I second Rebecca's recommendation of London Walks. I did the Stonehenge trip with them, plus numerous other walks within London. In my experience, the London Walks groups comprise travelers from around the world, including the UK, who are looking for the experience LW offers. People get chatting. It is fun. No need to panic that you need to make all connections on your own. Follow their directions and show up at the designated train station and designated spot (maybe track number or some other landmark). Then, kick back and enjoy.

How to get from Victoria to other train stations? Use the Transport for London website: https://tfl.gov.uk/plan-a-journey/. Play around with it. Even if you did not want to use the tube, I bet you can find buses that go where you want. This site is so great, it even lets you say if you want to avoid escalators (which I frequently do). Like Nordheim, I am an advocate for bus travel if it is convenient as you get to see things and gain an understanding of locations and proximities that using the tube may not provide.

Have fun!

If you go to Oxford, instead of taking a train, I recommend you take the Tube bus line which departs from Marble Arch and arrives at Gloucester Green (the bus station) in about 1 hour. From there, it's any easy walk to all the sights in Oxford. The Oxford train station is not as close to the major tourist sights.

At least two people have spoken of taking trains to Leavsden for the Harry Potter.

It is Leavesden - note the middle "e".

There are no trains that go there because there is no station there.

London Midland trains go from Euston Station to Watford Junction from whence a bus leaves from stop number 4 across the forecourt direct to the studio tour.

All London Midland trains follow the same route out of Euston heading north to Birmingham, Crewe, Northampton, Milton Keynes, Tring or Watford Junction, but they vary in where they stop and how long they take.

They pretty much follow a clock-face schedule, leaving London at the same times each hour, with slight differences at each end of the day and weekends.

Generally the xx:49 towards Birmingham or Northampton and the xx:54 towards Northampton are the fastest, stopping at Watford Junction as the first stop.

There are also slower trains at xx:04 and xx:34 to Tring, and xx:24 to Milton Keynes Central which make 1,2, or 3 stops before Watford Junction.

There are also 2 trains an hour from platform 9 or 10 by the orange coloured Overground trains which stop at every station and take much much longer. They are the same price as the London Midland ones so I don't suggest to use the Overground on that route.

Somebody suggested that you can use Oyster for all of your day trips. You absolutely positively can NOT use Oyster for journeys to Stonehenge, Cambridge or Oxford.

Oyster is only for use in areas covered by Transport for London. For tourists that means only in the 6 main London zones plus Watford (which has a special Oyster fare). It is train tickets to the others.

I would only consider taking the coach to Oxford if I were staying close to one of the stops of either company (Victoria, Marble Arch, Notting Hill Gate, Baker Street, Shepherd's Bush or Hillingdon) as point to point it takes rather longer, but if it is on your doorstep the total time might be reduced. Advance tickets on the rail route can sometimes work out cheaper than the coach, albeit tying down your time of travel. All have offers from time to time. The coach station is marginally closer to the centre (5 mins walk) and the advertised journey time is 100 minutes.

Many thanks to all who replied. I am persuaded to try the bus system, and London Walks. I really appreciate your suggestions.

tween,

If you're staying near Victoria Station you'll also have easy access to the Victoria Coach Station, which is a short distance from the Victoria Rail and Tube station. National Express Coaches also go to the places you'll be visiting, but will take longer. Check their website for details.

You might also want to consider Evans Evans day tours to Stonehenge. We did that a number of years ago. In fact we took numerous tours with them. We also took the train out to Cambridge and to Oxford. Right after you get off the train, at either place, it is easy to find Hop On/Hop Off buses. We enjoyed doing the Cambridge tour - two different times. We felt we learned a lot and saw a lot of both towns.