Table 4 summarizes investment benefits under a number of
different timetable assumptions. Appraisal A (row 1) compares the
current situation with the planned situation.This is a reasonable
alternative,although it potentially adds the effects of the investment as such with the effect of the timetable change as such.Appraisal B(row 2) assumes that train frequencies are increased
regardless of whether the investment is built.This is a common
assumption in appraisal practice :a planned target timetable is
assumed, and investments are evaluated assuming the same
timetable. Appraisal C evaluates the investment at the current
frequency,thus separating the effect of the increased frequency
from the effect of the investment,although obviously not using the
new capacity to its full extent.Appraisals D and E assume that
train frequencies are set to maximize operator profits and social
benefits, respectively,in both scenarios.