Buying an international train ticket at this city's main station is already a nightmarish experience on some days, with travelers often waiting for as long as an hour to talk to an agent.
So it was more than a little ominous when the train station released a study earlier this year of what could go wrong when the Netherlands and most other European countries start replacing national currencies with euro notes and coins on Jan. 1.
If the ticket agents are not prepared with enough cash, or are not ready to accept guilders while making change in euros, the study suggested, waiting lines could swell from about 100 people to nearly 1,200.
Worst-case scenarios are typically worse than reality. But the warning did highlight one of the biggest headaches Europeans and people traveling in Europe face in switching to euros as a cash currency: For at least a few days after New Year's, businesses will struggle with countless customers who want to pay in their old currency and receive change in the new one.
Less than three months remain before euro notes and coins begin to replace the national currencies of 12 European nations. For travelers who hop back and forth across national borders, the ability to use one currency in most of Europe will come as a relief. But it could also come as a jolt, and officials are quietly worried about the potential for mischief amid the confusion.
Will hotels, restaurants and other businesses effectively raise their prices by rounding up to the next euro as they convert prices from lire or francs to euros? Will counterfeiters deploy fake bills before people learn how to recognize the euro's intricate security features?
But perhaps the biggest source of headaches will be the need to deal with two currencies simultaneously, for as long as two months.
For instance, many of the people lining up to buy tickets at the Amsterdam station will be paying in their old currency, because euros will not become generally available until Jan. 1. But stores will be issuing change in euros, not only because the old currencies will soon cease to be legal tender but because customers will want to unload their old money.
Cashiers will need two sets of cash drawers. If cash registers are not programmed to make a currency conversion, the cashiers will need calculators by their side.
It will be bad enough for the Dutch ticket agent and for tourists double-checking their change, who will have to divide guilders by 2.20371 to get euros. But at least Dutch customers have an exchange rate that is not far from two to one, making it easier for them to perform rough price conversions in their heads.
Consider the math facing store clerks in Italy, where one euro will be worth 1,936.27 lire. As of Jan. 1, a 3,000-lire ice-cream bar should cost 1 euro 54 cents. The change from a 10,000-lire bill would be 3.61 euros.
Travelers who arrive on Jan. 1 or later can simply start out with euros. But people who are traveling before the New Year will have to use the old currencies through Dec. 31 (most nations will accept their old currencies until about March 1) but are likely to get euros as change, starting Jan. 1.
The scale of this new-currency introduction is unprecedented: 12 countries across Europe will drop their old currencies at the same moment and adopt the new one. Britain, Denmark and Sweden are the only European Union members that have refused to adopt the euro. The logistics entail an estimated 14-billion to 15-billion new bank notes and about 1.55-billion coins.
Worried that counterfeiters would try to swindle people in the first days of the changeover, the European Central Bank refused to let the public see any real notes and coins until Aug. 30, and it will not let people touch them until the end of the year.
The bills do have elaborate counterfeiting safeguards, including a foil hologram that, when the bill is tilted, reveals the euro symbol and bill's denomination.
Beginning in September, national central banks across Europe shipped the new currency to banks, which will make it available to stores in November or December. Consumers will not lay their hands on any notes and coins until the last week of December, when they will be able to buy starter kits with enough money to make a few small purchases.
Across Europe, automated teller machines will be loaded up with euros in the early hours of the morning on Jan. 1. Currency exchange booths, including those in the United States, will be stocked and ready for business as well.
Big retailers, like Metro A.G. of Germany, plan to post prices in both German marks and euros, phasing out the mark prices over the next two months.
But many smaller shops may be less prepared. A European Commission survey found that, as of March, only a quarter of small- to medium-size businesses considered themselves ready for the euro.
As for those non-Europeans who are holding some foreign currencies, the time to conveniently exchange this for euros will be brief.
For instance, France will honor the franc as legal tender for purchases until Feb. 17 and for exchanging into euros at commercial banks until June 30, according to Chris Matthews, a spokesman for the European Commission in New York. After that, francs can be exchanged only through France's central bank in Paris or its branches; coins for at least three years, banknotes for 10.
Italy will accept lire for purchases until Feb. 28, he said. It has not yet been decided how long commercial banks will make exchanges, but it will be at least until the end of February. Both coins and banknotes will be accepted by Italy's central bank in Rome or its branches for 10 years. For a chart of exchange deadlines, see www.euro.ecb.int/en/section1 /travelling.html.
Early on, long lines at cash registers are predicted, as clerks and customers learn to operate with two sets of currency. In the long run, the euro should make life easier for visitors to Europe. But those traveling right before or after the switch should acquire as little of the old currencies as possible, use credit cards and carry a calculator.