Have a technical question to do with the relative costs of building a cycle bridge versus an underpass for a cycleway to cross a two-track railway line, where there is space for either option.
An underpass is preferable, as the Dutch would provide:
- The height change doesn't have to be so great as for a bridge.
- People on bicycles find it easier: naturally accelerate down the hill, then use momentum to cost up the other side. A bridge requires effort to climb and then braking that wastes energy on the other side.
But, roughly-speaking, which is cheaper?
A bridge, given the larger height difference, will need more space. But a bridge might be available off-the-shelf and it requires fewer earthworks and has fewer drainage problems. It also doesn't need any modifications to the railway itself.
So I'm guessing an underpass is more expensive, but by how much?