Title: Integrating car path optimization with train formation plan: a non-linear binary programming model and simulated annealing based heuristics,
Abstract: An essential issue that a freight transportation system faced is how to
deliver shipments (OD pairs) on a capacitated physical network optimally; that
is, to determine the best physical path for each OD pair and assign each OD
pair into the most reasonable freight train service sequence. Instead of
pre-specifying or pre-solving the railcar routing beforehand and optimizing the
train formation plan subsequently, which is a standard practice in China
railway system and a widely used method in existing literature to reduce the
problem complexity, this paper proposes a non-linear binary programming model
to address the integrated railcar itinerary and train formation plan
optimization problem. The model comprehensively considers various operational
requirements and a set of capacity constraints, including link capacity, yard
reclassification capacity and the maximal number of blocks a yard can be
formed, while trying to minimize the total costs of accumulation,
reclassification and transportation. An efficient simulated annealing based
heuristic solution approach is developed to solve the mathematical model. To
tackle the difficult capacity constraints, we use a penalty function method.
Furthermore, a customized heuristics for satisfying the operational
requirements is designed as well.