Hullámvasút, Wooden roller coaster in Zugló, Hungary.

Hullámvasút is a wooden roller coaster in the Zugló district of Budapest, Hungary, with a track about 980 meters long, 17 meters high and a maximum drop of 45 degrees. Its trains have three cars, each with five rows of two seats; a brakeman rides in the first row of the middle car and controls the speed by hand. The structure is entirely of wood and operates by gravity, with a cable lifting the train to the first crest.

Designed by Ervin Dragon, the coaster opened in 1922 as the Hegyivasút in the Angol Park, on the site of the earlier, smaller Amerikai Magasvasút. It reached its final form by 1926 and was damaged during the war, leaving the present track somewhat shorter than the original. It closed with the Holnemvolt Park in autumn 2015 and has been a protected monument since 2013.

The name Hullámvasút is Hungarian for "roller coaster", literally "wave railway". The ride opened in 1922 as the Hegyivasút (mountain railway) and was later renamed. Its six trains carried dragon-shaped noses and side panels for decades; the noses are now plastic replicas, and the cars keep their numbers and two remaining colours, ochre yellow and green.

Hullámvasút has been closed since November 2015 and is no longer in operation, so visiting as a ride is not possible. Those interested in the site can explore the surrounding area of the Városliget city park in Budapest, where the former amusement park once stood.

A dedicated brake operator rode on every train and controlled the speed by hand, because the Side Friction system used on this coaster had no automatic speed control. This practice was common in early 20th-century coasters but is virtually unseen in any park today.