Line (Denmark's first high-speed rail) in 2019. Network Tracks Banedanmark is in charge of 2,045 km of railway lines, which do not include the lines controlled by private railways. All Danish railways are (standard gauge), with the exception of a few narrow gauge museum railways; gauge was previously common on branch lines, with being prevalent on industry railways, such as those for transporting sugar beets. The narrow gauge lines generally disappeared during the 1950s and 1960s. The maximum speed allowed on main lines is generally 180 km/h, with less trafficked lines usually allowing between 75 and 120 km/h; the speed may be lowered in places due to the condition of the track. While wooden sleepers are used on sidings and branch lines, concrete sleepers are the norm on all main lines; the common two-block concrete sleepers are now being phased out in favour of monoblock ones. The age of the tracks in Banedanmark's network has become increasingly problematic in later years. A 2002/03 analysis of Banestyrelsen's (now Banedanmark) network states that the average age of the track is too high, with a present average age of 24 years compared to the recommended 20 years. Banedanmark also owns the S-train lines, but does not own every railway in the country. It does not own local railways around Hillerød (such as Frederiksværk Line and Gribskov Line) and Østbanen, Odsherred Line, Tølløse Line, Thy Line, Lemvigbanen, Aarhus Letbane and Copenhagen Metro. Electrification General-purpose electric propulsion was adopted quite recently in Denmark; the political decision to electrify the main lines was made in 1979. The first line to be electrified was Copenhagen–Helsingør, electrified in 1986, followed by the main line across Zealand, Funen and Southern Jutland in the 1980s–90s. On the main lines that are equipped with them, the overhead lines carry 25 kV AC at 50 Hz. The system is used on the main line from Sweden through Copenhagen to Fredericia, and from there to Padborg and the German border. Both Sweden and Germany use 15 kV at 16 Hz and 16.7 Hz respectively, and the multi-system class EG goods locomotive is equipped for both 25 and 15 kV. The S-train network in Copenhagen operates at 1650 V DC, supplied from overhead lines; the Copenhagen Metro uses 750 V DC, supplied from a third rail. It was the first electric network in Denmark, electrified around 1930. Since there are heavy delays (several years)