A set of aluminium rails that goes slightly down. After about 8 meters the left rail curves 90 degrees left and the right rail stops. A new rail startes in the right side after the curve which is also around 8 meters long.
Take the train to Allerød station. At the station, go to the opposite side of the pedestrian street and turn right down the "main road". After around 1 km you'll find the rails on your left hand. You can also find some rails on your right hand - they go down to a tunnel under the road.