Chelsea-Immes tunnel
 The Chelsea-Immes tunnel under construction | |
| Overview | |
|---|---|
| Location | Oftbon Channel |
| Status | Active |
| Start | Oftbon, Elbresia |
| End | Immes, Elbresia |
| Operation | |
| Opened |
|
| Character | Passenger trains, freight trains, vehicle shuttle trains |
| Technical | |
| Line length | 70.46 km (43.78 mi) |
| No. of tracks | 2 single track tunnels 1 service tunnel |
| No. of lanes | 4 lanes (2 lanes per direction) |
The Chelsea-Immes tunnel is a 70.46 km (43.78 mi) road and railway tunnel that connects mainland Elbresia to Oertor Island, granting a direct non-ferry route to the most populous region of the country in Oftbon. It is one of two fixed-links between Oertor and mainland Nortua, the other being the Mont-Cliffes Bridge. At its lowest point, it is 75 metres (250 ft) deep below the sea bed and 115 metres (380 ft) below sea level. At 57.9 kilometres (35.9 mi), it has the longest underwater section of any tunnel in the world, and is the second-longest railway tunnel in the world. The speed limit for trains through the tunnel is 160 kilometres per hour (100 mph), while cars are limited to 80 kilometers per hour (50 mph). Every day the tunnels service nearly 80,000 people.
The tunnel began construction in the early 2000s, but construction costs and delays pushed the opening date to 2017. Since its construction, the tunnel has experienced a few mechanical problems. Both fires and cold weather have temporarily disrupted its operation.