I've never had much luck with US credit cards in European train stations. I did try again last time at AMS, and ended up going to a ticket window as usual. I suppose at certain times there could be lines, but I've never really had a wait.

Best bet if you have a US card is either go straight to the ticket window, unless you have cash, preferably exact.

Also, as the OP may not be that familiar with the trains, it may just be easier to go to the ticket window to ensure he doesn't make a mistake. I've certainly used that method in a few places around the world!

I read in a guidebook that if I want to buy two one ways (Leiden--Haarlem, Haarlem--Hoofddorp), I will be charged €1 surcharge per ticket. If I go to a ticket window, I will be charged €0.50 surcharge per ticket. So the surcharges aren't combined at a ticket window to €1.50/per ticket?

Also, can I buy these one ways in advance from a ticket window or machine (whichever is less money) from Amsterdam Centraal even though I'm neither beginning nor ending a rail trip there the following day? I'm arriving at Amsterdam Centraal from Hagen, Germany and would rather buy the next day's tickets when I arrive in the Netherlands and get it taken care of instead of doing it the following day. Thanks.

The two surcharges are for different reasons: The 1 EUR surcharge is because you're buying a disposable single-use chipcard rather than loading it onto a plastic chipcard, and the the 0,50 EUR surcharge is use of the ticket window. Indeed they will be summed up to 1,50 EUR if you buy a disposable single at the ticket window.

Ticket machines that accept cash only accept coins.

Thanks.

Will it still give change meaning if the fare were €5 and I paid with three €2 coins, would I get €1 change back?

What about my question about buying 2 one way single-use chip card tickets a day in advance from a different train station than the ones I will go to the next day? Can I do that?

Yes, you will be given change.

I don't know about buying tickets the day before. They do have a date on them, so I tend to think you can't use them the day after.

Thanks.

Got it. So one can't select a specific date from the ticket machine is what I'm hearing; the date of purchase is the default. Thanks.

Can r/t tickets be bought either from the machines or from real people?

You should be able to buy them from both but remember:

-If you are travelling out and back on the same route the same day, buy a Day return
-If you are travelling back another day, you will need two Single tickets
-If you bump into baccarat_king say hi from me
-If you bump into me i'm sorry

Same day return can certainly be bought from the machine.
I think since recently it has been possible to buy a ticket for a date up to a week later. Remember that even though a ticket can be dated, you are still required to tap in and check-out.
As far as I know, the machines are only in Dutch or English.
Machines take VISA and MC but only with PIN. There is an extra surcharge of €0,50. Maestro is free.

Great tip: if you have access to a printer, you can buy a home-print ticket from the Belgian Railways via their site. Here you can choose your specific date and route in advance, even if it's only between two Dutch stations. You also circumvent the surcharge for the disposable chipcard. You can pay with VISA or Mastercard for free, AMEX has a €2 surcharge (per order). Unless you are on the Thalys, the ticket is valid for any train on your selected day so there is no need to select a specific timing.
The tickets are personal so you'll have to provide your full names. They will then be send to your email address and you will have to print them. You have to be able to show your ID if asked, to match the ticket.
You do not have to tap in or out with this card. If you travel to a station where the gates are closed, there are special lanes where you can scan the QR code on the ticket to enter/exit.
Why the Dutch Railways can't offer this service (i.e. payment with creditcard) to visitors is beyond me. Then again, customer focus is not really their strength.

Where do you tap in and out on the train -- at the departure and arrival platforms or is this only for Thalys? I'm buying 2 one ways so would I even need to do this?

For some reason, I thought the ticket machines were only in Dutch.

You only tap it when you enter the station or as you approach the platform or on the platform itself, depending on the station. At Schiphol you touch in and out before you go down to the platform, at Amsterdam Central you touch in and out as you enter or leave the station.

I would be going between Leiden & Haarlem and later between Haarlem & Hoofddorp.

Two years ago when I only took the train between AMS & Centraal Station as well as Hoofddorp and AMS (a very short ride), I didn't tap anything. Is the rail system different now?

Yes, the exclusive use of the chipcard is fairly new. At the stations you mention you will most likely be tapping your card as you enter the platform area. There should be gates, so you're not very likely to miss them.