TEN-T Core Network In The EU

The TEN-T, or Trans-European Transport Network, is a "European-wide network of railway lines, roads, inland waterways, maritime shipping routes, ports, airports, and railroad terminals" with the goal of not only building new infrastructure but also reducing the environmental impact of transportation while increasing energy efficiency and safety. This massive project includes, but is not limited to, nine key corridors that mirror major long-distance transportation movements and routes across Europe. The TEN-T is the world's largest and most expensive construction project, with a projected total cost of €500 billion ($600 billion). Experts estimate that removing bottlenecks and deficiencies in the main transportation infrastructure will cost at least €250 billion.

It's unsurprising that the project is running behind schedule and over budget. It was started in 2013 and is no longer projected to be operational by the planned 2030 deadline. Changes in design and scope over time have "led to cost hikes of €17.3 billion (or 47 percent) compared to early cost estimates," according to a recent commission audit of the project.

Cost Estimation: $600 Billion by 2050