and Ilmenau over a length of 27.4 kilometres and rises temporarily to a height of around 600 metres above sea level. This section contains nine tunnels with a total length of 22.7 kilometres (83% of the tunnels by length on the line). The intervening valleys are crossed by nine bridges. In a 23 kilometres long section built alongside the A 71, the line is largely confined to a 40-metre-wide strip of land. The design speed is . The planned maximum speed was initially and was later raised to . One source from 2009 again refers to a planned maximum speed of . For the regional services south of Coburg that have operated since 2016, the maximum permissible speed has been reduced to . More than fifty percent of the length of the route consists of civil engineering works—a new record for German high-speed railways. The planned 22 tunnels have a total length of 41 kilometres. The two longest are the Blessberg Tunnel at 8,326 metres and the Silberberg Tunnel at 7,407 metres. Its 29 viaducts have a total length of 12 km. The longest is the 1,681 m-long Ilm Viaduct. In addition, another 46 road and path crossings are planned. The ruling maximum gradient is 1.25%. In four short sections, this was increased to 2.0% to reduce capital costs. Such sections were not planned until detailed planning began in spring 1994, but in mid-1994 seven such sections were planned with longitudinal grades between 1.778 und 2.00 percent over a length of 400 metres to 1.1 kilometres. The power supply was connected to the traction power network by means of two new spur lines running via three new substations at Roth, Ilmenau and Eischleben. The existing Ebensfeld substation was expanded for the power supply of the new line. There was no equalisation of the earth masses, which meant that about 16 million cubic metres of earth was deposited at 24 landfill sites. Near Masserberg. for example, 1.8 million cubic metres was dumped covering an area of 54.8 hectares, with a maximum height of 27 metres. The permanent surface requirements of the new line are around 435 hectares. In the construction phase, a total of around 1200 hectares was required. Around 990 hectares has been provided for environmental compensation areas. Erfurt–Ilmenau route description From Erfurt station, the route runs west on the northern side of the Gera valley, parallel to the tracks