A trip chain in which train is used as the main mode can be broken down into three
components, namely a main train leg and two non-train legs. In our analyses, we
make distinctions between the non-train legs in two different ways. First, we differentiate
between access and egress legs where the access leg is defined as the trip from
the origin to the boarding railway station while the egress leg is the trip from the
alighting railway station to the destination. Second, the non-train legs can be segmented
into home-end legs and activity-end legs. Besides differences in access and
egress modes, multi-modal trip alternatives differ in other attributes such as boarding
and alighting railway stations, train service types, transfer stations, and more. In
adopting a multi-modal trip alternative an individual faces multiple choices, each related
to the above stated trip attributes (see Figure 1). Many choices are closely related
and not independent. As an example, the attractiveness of the walk access alternative
may be dependent on the choice of boarding station