Any pension plan that bases benefits not solely on what money in the plan can cover, but on participants' earnings and work history, depends upon some minimum rate of return.
More specifically, it is defined as the minimum rate of return on investment that providers of capital require as a condition for investing in or lending to a railroad.
The cost of capital is the minimum rate of return on capital required to compensate investors (debt and equity) for bearing risk, their opportunity cost.
However, because the current construction finance rate already covers that minimum rate of return, we don't expect construction lending rates to increase immediately.