  Metro train operations is becoming more challenging due to overcrowding and
unpredictable irregular passenger demand. To avoid passenger dissatisfaction,
metro operators employ various operational strategies to increase the number of
train services using limited number of trains. This paper integrates metro
timetabling with several operational strategies to improve passenger services
with limited number of trains. We propose three optimization models for
timetable planning during both peak and off-peak hours: The first model aims to
minimize operational costs, the second aims to minimize passenger waiting time,
and the third is a multi-objective optimization model that considers both
objectives simultaneously. These models integrate operational strategies such
as rolling-stock assignment, short-turning, and skip-stop strategies to
increase the number of services with limited trains on a bidirectional metro
line. The paper also provides detailed calculations for train services, running
times, and station dwell times. The proposed models are then implemented on a
simplified Santiago metro line 1.
