It happens only in Amsterdam: during hot summers bridges get stuck. All of a sudden they don’t close or open any more. The warm weather causes the steel tram rails to expand. To be exact, this happens only above 28 Celsius. Local authorities cool down the bridges by running water over the tram rails, but it doesn’t help much. Yesterday the Hortus bridge was stuck, today the important Berlage bridge didn’t close. Very inconvenient for traffic.