What is your favorite subway system, and why?
Paris is my first love. You can get anywhere. I love maps and Paris metro maps are a thing of beauty.
As far as mass transit, Amsterdam's tram system is great. You can still see shops and attractions but has the efficiency of a subway. The actual subway system is ideal to get to the North from the South. My other fav is Istanbul's ferries. Seventy-five cents for up to an hour on a boat with indoor/outdoor seating and tea. I spent most of my time just riding the ferries for fun but in all honesty it was faster than the bus.
What are some of the most enormous subway stations that you know of? How do you deal with them.
Tokyo's Shinjuku: I stayed near there and just researched a ton but in the rush hour I just went with a directional flow (I needed to exit east) and hoped for the best. Same with Shibuya.
Paris's Chalet-Les Halles honestly I avoid like the plague as you could probably get off a stop earlier and walk and get out faster.
In London, I appreciate the signs they have with maps showing the exits and where on the map you can exit. They have the same in Paris on the actual exit signs and it makes such a difference.
What is your favorite airport for subway access to the downtown area it serves?
London City is a dream! Heathrow is direct but takes forever. Same thing with Munich.
Do you have any general tips to offer on the systems you know best?
London: often the "accessible" stations are not in any way accessible. They are getting better at making it clear if there is step-free access but often even then lifts will be out of order. If you are traveling with someone or you yourself have different needs when it comes to access or even just travelling with large cases, buses are going to be your best bet.
Paris: Arts et Métiers station on Line 11 is gorgeous and one of the most soothing spaces I've been in (is it the warmth of the cooper?)
Amsterdam: check an updated tram schedule before you go. Amsterdam have switched lines and numbers frequently, and at least yearly to adjust for where people live and work.
Berlin has a really great, integrated mass transit system. The trams, S-bahn, U-bahn and buses all work together well so you have multiple routes you can take. This is very handy in bad weather or when there is an accident on the roads. I used to race Google Maps and the Berlin transit app to see if I could come up with a better, more efficient route and often could just because there were so many routes.
What's your protocol for identifying optimal station exits?
Amount of steps, how far away it is from the platform (is it easier to go up quicker and then just cross the street instead of criss-crossing underground), does it spit you up in a precarious place (everyone crowded around a crosswalk on a busy street). The really handy station exits go straight into key department stores (Paris and Tokyo have this and during hectic shopping hours it's lovely!)